|
Think about how dependent you are on the land and its soils.
Your house rests on it. Your trees root in it, as do your garden
vegetables, flowering plants, and lawn grasses. The stability
of your buildings and the success of your plantings depend on
the nature of your particular piece of land and its soils. Gaining
an understanding of what formed your soil will help you to make
educated decisions on how to improve it.
The development of soil is a complicated process. Different
kinds of rocks at or below the earth’s surface — known
as the bedrock or parent material — are weathered into
fragments. These fragments are carried away by wind, ground
by glacier meltwaters, tossed in the ocean, deposited by river
floods, and moved by landslides. These fragments are also chemically
weathered, and some of the minerals within them are dissolved.
Decaying plants and other organic matter mix with the fragments.
Climate, new vegetation, water draining across the land, and
changes in land use all contribute to the continuing transformation
of the soils. These interactions may have taken place just yesterday
— a river flooding or a new development requiring fill
dirt that is trucked in from another site and mixed with the
native soil — or they may have taken place millions of
years ago.
Return to Index at top of page
Soils are categorized by type in soil surveys, which are documents
that have been completed for about 90 percent of Virginia by
the U.S. Department of Agriculture, Natural Resources Conservation
Service (NRCS), formerly the Soil Conservation Service. One
hundred and ninety different soil types have been identified
within the Potomac River watershed. Soil types are determined
by the rock from which they originated and how they were changed
by weather over time. Soil surveys were originally designed
to serve agriculture, but since 1960 they have been expanded
to serve suburban and environmental interests. Soil maps show
the geographic location of different soil types on the landscape.
Soil types are frequently given names indicating the location
where the soil was first discovered. For example, soil type
number 47 in Prince William County is known as Quantico Sandy
Loam. Soil maps are useful for planning purposes and as an initial
guide but may not be specific or accurate enough to help you
with questions about your backyard vegetable garden.
The ideal soil for a garden is deep, crumbly, and well-drained.
It is rich in nutrients and organic matter and active with microorganisms.
It usually has a pH between 5.5 and 7.5 (for nonacid loving
plants). A compacted soil may prevent roots from spreading and
prevent water from soaking easily into the ground. Not only
does this short change your plants, the extra runoff may lead
to erosion and stream degradation. A sandy soil, low in organic
matter, often holds very little water. In such a soil, the benefits
of rains are often short-lived, and garden chemicals can more
easily leach from the root zone into the groundwater.
Soil Texture and Structure
Soil may be loose and crumbly or hard and massive. The texture
of a soil is determined from the proportion of its particles
of sand, clay, and silt. Sand grains are large enough to be
seen and felt individually, silt particles are medium-sized
like flour or chalk dust, and clay particles are microscopically
fine. An easy field test to determine the clay content of your
soil is to squeeze a handful of soil in your fist. If it crumbles
easily, the sand content is high. If it squeezes easily into
a “snake,” the clay content is high.
Soil pH
Level Soil pH is an indication of relative acidity or alkalinity.
It is reported on a scale of 0 to 14, with low pH numbers being
acid and high pH numbers alkaline. A pH of 7 is neutral. Most
plants do well in Virginia in a neutral to slightly acid soil.
Soil Drainage
Do you have puddles in your yard? Or does water rapidly disappear
into the ground? Does water travel across the surface of your
yard? Drainage describes how well your soil handles and moves
rainfall, surface, and subsurface water. Well-drained soils
will not pond and will not remain soggy for long periods of
time. These soils are generally the most suitable for building
sites and allow the most versatility in plant selection. Poorly
drained soils have groundwater tables within a few inches of
the ground surface or even at the ground surface during wet
periods of the year.
Soil Permeability
Permeability refers to the ability of your soil to transmit
water or air. The permeability of your soil will affect your
choice of a drainage system, sewage disposal system, plants,
and building construction techniques. Soils that are high in
clay or have little space between particles for the movement
of water or air usually have low to very low permeability. Poorly
drained soils hold water and present challenges for landscaping,
yard drainage, and maintenance of a dry basement.
Your soil may also have a layer of material that restricts
the downward movement of water during wet periods and results
in a temporarily perched groundwater table. This layer may also
stop the roots of your plants. During dry spells, your plants
may require additional water. Test the permeability of your
soil by pouring water on it. Give it a few minutes, and then
dig. How deep did the water penetrate? Remember this when you
water your garden or lawn. Time your watering, and gauge the
amount of water needed to reach your plant’s roots based
on your research.
Soil Depth
Most native or natural soils are made up of varying layers,
called horizons, that have developed over the rock from which
they were formed. Beginning as a thin layer of material on rock,
they are continually transformed by climate, drainage, and vegetation.
A soil profile is a vertical slice of earth that depicts the
structure of the soil from the earth’s surface down to
bedrock. The upper several feet of soil are the most important
to the homeowner.
Soil Erodibility
Soils are categorized as to how likely they are to wash or
blow away. The most erosive soils are ones that are silty or
sandy. Soils on moderately to steeply sloping areas are more
likely to erode than soils on gentle slopes. Vegetation should
be established as soon as possible on any bare soil area.
Return to Index at top of page
You may find that your soil is unlike any described for your
area. This could be because the native soil was greatly altered
during the construction of your house through grading, compaction,
removal, or burial. Improving your soil structure is one of
the most important aspects of soil care, and adding organic
matter is the most effective way to accomplish this.
A soil test will give you an inventory of the minerals in your
soil affecting plant growth. A rating of low, medium, or high
is given for magnesium, calcium, phosphorus, and potassium.
No test is made for nitrogen, a relatively unstable and short-lived
nutrient. Nitrogen must, in most cases, be applied annually
and tailored for the particular plant to be grown.
Soil pH is also reported on the soil test results. In Virginia,
chances are that your soil will need an application of lime.
Be careful to follow the directions and to apply the recommended
lime in accordance with the application rate and at the right
time of year. The same holds true if fertilizer is recommended.
Lime and fertilizer washed off the land by heavy rains don’t
help your plants, and they contribute to stream pollution.
How Frequently? Test your soil every three years. Always
fill out the soil test information sheet as completely as possible.
Lab recommendations are partly based on information you provide,
such as soil texture (sandy, loamy, or clayey), last lime application,
and what you intend to grow in that area.
Where Do You Get a Soil Test Kit? Call your local Soil
and Water Conservation District or your Virginia Cooperative
Extension agent. Mail soil samples to Virginia Tech or a private
lab for analysis. There is a small fee.
First, make an honest assessment of your conditions. Decide
what deficiencies are worth the effort to change and what makes
more sense to leave as is. For example, if your soil is sandy,
clayey, or has been compacted, till in organic matter and mulch
liberally for several years. Plant cover crops each year until
your soil is improved. If a proposed planting site has a high
seasonal groundwater table, it may be feasible to drain the
area with swales or subsurface drains. However, if your ground
is very rocky, perhaps a rock garden is the most appropriate
solution.
Adding Organic or Composted Matter
Many local soils are naturally low in organic matter. Their
productivity as well as their workability can be greatly enhanced
by mixing additional compost into the top 4 to 6 inches of soil.
Organic matter acts as a sponge, soaking up excess moisture
and gradually releasing it as plants need it. It also enhances
the soil’s structure and helps to maintain the appropriate
pH balance. Peat moss, composted leaves, crop residues, or straw
should be tilled into garden soil in the fall and winter. At
the same time, grass clippings, manure, or fertilizer should
be incorporated to provide the extra nitrogen required to help
break down the dry organic materials. This material can be composted
and added to the garden in the spring if you prefer. This is
particularly true if you are adding manure, as it may “burn”
plants if it is too fresh.
Adding Nutrients
If your soil test recommends additional nutrients, add them
at the appropriate time for the plant and according to the directions.
Excess nutrients can run off and pollute nearby streams.
Tilling Your Land
Use a rototiller if your area is too large or the soil is
too hard to hand dig. Never till your soil when it is wet. This
may destroy the soil’s structure. For established lawns
tilling is very beneficial, particularly for hard or dense subsoil
conditions. Aeration encourages greater root depth and improved
water intake.
Return to Index at top of page
Soil erosion occurs when soil particles are carried off by
water or wind. In addition to the soil, runoff can wash fertilizer
and other pollutants along with it. Most phosphates and pesticides
entering Virginia’s waters are attached to these soil particles.
Nitrogen and phosphorus from fertilizers carried by runoff have
been associated with many environmental problems. Streams, ponds,
rivers, and the Chesapeake Bay suffer from algae growth, depletion
of the water’s oxygen supply, and suffocation of aquatic
organisms.
Everyone recognizes a gully as evidence of soil erosion. Muddy
water in your gutter or driveway also indicates that erosion
has been occurring. It may only be visible for a time following
a rain, but the damage will continue unless something is done.
The following are other indications of erosion.
- Bare spots on your lawn or property
- Exposed tree roots
- Small rills or gullies on slopes
- Soil splashes on your windows and outside walls
- Sediment that collects in low areas or on pavement
To solve the erosion problem, you must identify the cause and
then correct it with some type of conservation practice. If
you have a problem with excessive stormwater runoff from an
adjacent property, the solution may involve that property. A
long-term solution often involves analyzing the entire watershed.
Fixing Bare Spots on Your Lawn or Property
Excess water is the most frequent cause of bare spots and erosion.
If the excess water is moving across your property, redirect
it to a more appropriate spot with a diversion made of logs
or earth berms. The redirected water can then be diverted to
an appropriately planted grassy area, a dry well (an underground
reservoir filled with stone and lined with filter fabric that
detains the water until it seeps into the soil), or an underground
drain pipe. For all but the smallest diversions, you should
contact a specialist for advice. If your bare spot is caused
by standing water, you will need to regrade the surrounding
ground to encourage the water to move where you want it to go.
Plant or mulch the area once you’ve redirected the water
or regraded the ground. If little soil is there, till topsoil
into the bare spot before planting. Be careful not to create
a new dam by raising the height of the ground surface! If the
area is steep or small, sod or other plants may be more appropriate
than grass seed. Any kind of cover (grass, straw, or mulch)
can reduce erosion. In shade or heavily trafficked areas, a
permanent path of stone, woodchips, or gravel may be your best
answer. If you make use of pavement, consider using a porous
pavement or concrete, brick, or stone placed in sand that allows
some of the water to drain through the open spaces into the
ground.
Avoiding Soil Splashes on Windows and Outside Walls
Runoff from the roof may be overflowing from the gutters, splashing
soil onto your windows and walls. A concrete splashblock at
the downspout outlet or an underground pipe may control this
type of erosion. The outfall of the pipe may present a similar
erosion problem. Direct the gutter runoff toward a grassed or
other planted area, stream, street gutter, or dry well. Runoff
from the roof may also be directed into a barrel with a gutter
spout and stored for later use.
Ridding Your Land of Dirt Puddles
Whether your home is new or old, you are likely to have muddy
puddles. Children love puddles, but they are a sign that you
have an erosion problem. You will need to reshape the ground
surface by grading to redirect the water runoff. Fill the depressions
with additional topsoil, and replant.
Removing Small Rills or Gullies on Slopes
Groundcover is the most common solution to eroding slopes that
are too steep for grass. An eroded slope needs to be smoothed
and then planted with groundcover seedlings spaced 12 to 18
inches apart. It will take at least two years to establish,
so use mulch or temporary seeding in the meantime to help prevent
erosion. If runoff from sloping land causes damage on your property,
you can divert the water away from the trouble spot. Construct
a diversion of earth, brick, stone, or treated wood that directs
the flow of water.
Terracing is another way to address erosion problems found
on slopes. The steeper the slope, the greater the potential
for an erosion problem and the more difficult it may be to solve.
Slopes may be regraded into a series of terraces. The terraces
can be held with retaining walls or planted with grass or groundcovers.
If you plan to mow grass on the terrace slopes, be sure to make
each slope three times wider than it is tall. The terrace itself
must be graded with a slight slope to ensure that you don’t
create a puddle or that it doesn’t erode. Wide bench terraces
with sloping banks protected by vegetation or retaining walls
are often the most practical treatment for steep slopes around
buildings. Good topsoil should be removed and stockpiled before
excavating or grading so it can be replaced as the final surface.
You may need professional design help to create retaining walls
that have adequate foundations and drainage.
Check with your local government to determine if permits for
wall construction are needed or if there is a drainage easement
on a portion of your property. These are shown on your plat.
Return to Index at top of page
Water always takes the easiest path. Because of this, it is
important to understand how and what drainage is in order to
find an alternative path for the water on your land. Of course
water flows downhill. What is confusing is that when water flows
downhill, it may end up in a stream several hills away from
your land. How does it get there if it is always taking the
easiest path? An understanding of what makes up a watershed
may help to explain the answer.
Airplane travelers have the best opportunity to see watersheds.
From the air you’ll see lakes and rivers fed by many small
streams. The area that drains to a common stream, lake, or river
is called the watershed. Each of the small tributary streams
has its own tributaries; thus each has its own small watershed.
Watersheds can be very large, like the 64,000 square mile drainage
basin of the Chesapeake Bay. They can also be very small. Try
to find the boundaries of your neighborhood stream’s watershed.
Identify the ridgeline or other barrier that divides the water
that runs to your stream from water that runs to another stream.
Rainwater reaches a watershed’s stream in two ways, either
by running off the surface or soaking into the ground where
it flows beneath the surface of the earth to a stream. Like
surface water, groundwater also tends to flow downhill, through
the soil and fractures in the bedrock. Emerging through springs,
groundwater feeds the creeks between rainstorms.
What drains from your property will affect much more than your
land alone. Water supplies are threatened by overuse and contamination.
Pollutants in water are frequently referred to as point and
nonpoint source pollution. Point source pollutants come from
an identified point such as an outfall pipe at an industrial
operation. Nonpoint source pollutants come from many sources
such as pet waste, leaking or improperly disposed auto fluids,
car wash detergents, or fertilizers from your lawn. Pollutants
are carried down into the groundwater table with percolating
water draining through soil. Pollutants are also washed into
lakes and streams via surface runoff. Storm drains, along streets
and in backyards, lead to local streams. Home lawns and landscapes
contribute to pollution when improper water management and chemical
application allow fertilizer or pesticide-laden runoff to drain
into our water supplies.
Groundwater Table and Percolation
In some areas, soils are very slow-draining and are referred
to as having a high groundwater table. Groundwater tables tend
to be at their highest in February and March in Virginia as
a result of snowmelt and rains. In areas with a high groundwater
table, avoid digging a basement or take special measures to
keep basements dry. These may include reinforced concrete foundation
walls with special attention paid to waterproofing, foundation
drains, and sump pumps. You may also want to lower the subsurface
groundwater level with an underground drainage system.
Runoff
Before your house was built, rain fell evenly over the ground
where it stands. Most likely, grass and shrubs or a canopy of
trees kept the soil open and porous. Even in a hard rain, two-thirds
or more of the water soaked into the ground as it fell. Now
the rain pours off roofs, parking lots, sidewalks, and driveways
(all of which are impervious surfaces) and is often channeled
to underground stormwater sewers that pipe the water away from
your property. The ground around your house is often compacted
as a consequence of building construction. This compaction may
reduce the amount of infiltration and increase the runoff 2
to 10 times as much as the same land in forests or farms. Runoff
from your yard is the water that runs across your yard and all
the material the water picks up and carries with it.
Grading
The fill around your house should be properly compacted and
graded to slope away from your house at least 5 percent for
a minimum of 10 feet, making the ground 6 inches lower than
the ground surface at the house wall. This will drain surface
water away from the wall and help prevent water from standing
against the wall and potentially seeping through it or causing
water pressure under the basement floor. Planting and mulching
around outside walls should be done carefully to preserve drainage
away from the wall.
To help prevent surface water from standing in your yard, don’t
create or maintain a perfectly flat space. Maintain a slight
slope that drains toward a swale, rain garden or storm sewer
inlet. If you can’t do this, some type of underground pipe
and gravel drain with a sump may be necessary. Even very well-drained
soils may become saturated in a Virginia summer thunderstorm,
so try to maintain a slope of 5 percent away from the house
and 2 percent everywhere else.
Wet Lawns
If your yard, or some portion of it, remains wet and soggy
for extended periods (two or three days following a rain), the
natural drainageways may be blocked or have settled and do not
have enough grade to drain. Soggy ground and wet lawns are often
the result of trapped surface water with no place to go. Most
yards are originally graded so that water flows from the front
to the street and from the back to a swale, ditch, or storm
sewer. A swale is also normally provided between houses along
the property line to the front or rear or both. You may have
inadvertently changed the existing grade of your land with a
patio, walk, or mounded planting beds, or trees may have grown
significantly and their roots raised the ground surface. If
your yard is so flat that you cannot get good flow or if you
have a high groundwater table, then some kind of subsurface
drain may be needed. A 2-foot-deep trench with a perforated
pipe surrounded with gravel to collect this standing water and
lead it to a suitable outlet may be effective.
Wet Basements
Water can enter your basement in one of three ways.
- Through cracks in the basement wall
- Through the joint between the basement wall and the basement
floor
- Through the basement window well
Check the exterior grading to ensure that surface water flows
away from your house. With the passage of time, soil often settles
around the foundation wall. Water ponds in these settled areas,
and what doesn’t evaporate may find its way into your basement.
Flower beds and other plantings may hold water against the wall.
When regrading, avoid placing soil next to wood or siding. Examine
the window wells, and ensure that all contacts between the outer
foundation wall and the window well casing are well sealed.
A window well cover may be a useful addition. Also check for
clogged gutters and downspouts. Directing rain water away from
your house and extending roof drainage outlets to 6 or more
feet beyond your foundation often can prevent or correct a wet
basement problem.
If water is entering through the wall, the parging (exterior
mortar coat) or waterproof seal is cracked, too thin, or missing.
You should consult with a contractor. If the wall is merely
damp on the inside or seeps are visible, you may be able to
cure the leakage by coating the interior wall with a waterproof
cement-sand mixture.
If water is entering through the joint between the wall and
the basement floor slab or through cracks in the floor, water
pressure exists beneath the floor. First correct the surface
drainage to force surface water away from the wall, and then
check for the presence or absence of footing drains. If you
don’t have construction drawings of the wall footings,
try to get them from the builder or your local jurisdiction’s
Building Inspector files. Check for the presence or absence
of an exterior drain by looking for a plastic pipe discharging
at a point in your yard below the level of the footing or, if
a storm sewer inlet or manhole is nearby, looking inside it
to see if there is a plastic pipe through its wall from the
direction of your house. If the drain is there, but there is
no flow and your basement continues to leak, the pipe may have
become plugged with earth or tree roots over time. Correcting
this can be a major job. It may require snaking-type equipment
to reopen plugged drains along all or part of the length of
the footing. Occasionally, a deep penetration of frost followed
by some thaw and a heavy rain will temporarily restrict the
flow from the surface to the drain.
The presence of an interior under-floor drain is generally
confirmed by the presence of a sump. If the sump is full of
water and there is no sump pump, have one installed by a licensed
plumber. If there is a sump and working pump but water still
comes up through the floor joint or cracks, the perforated drain
under the floor may have become plugged, or the pipe may have
been laid incorrectly so that it does not drain by gravity toward
the sump. The latter case is most likely where heating ducts
are embedded in or under the basement floor. Correction of either
problem may entail breaking up the floor slab to get at and
clear or reinstall the drain pipe. Most building codes require
that, wherever possible, the discharge line from a sump pump
be connected to a storm sewer. If no storm sewer is located
nearby, the discharge pipe must empty into a drainage swale,
ditch, or stream that will carry the discharge away from your
house without causing problems for a neighbor. If a sump pump
is set up to discharge at the exterior of the foundation wall,
extend the discharge pipe so that water runs away from the house.
Gutters and Downspouts
Among other purposes, the gutters around the edge of the roof
are intended to collect the water before it drips down the side
of the house and puddles in the soil near the foundation. The
gutters should be firmly and tightly attached against the face
board (fascia) at the eave ends. If they are not, water may
seep between the gutter and the face board, rotting the face
board and soaking the walls. Gutters are sloped to downspouts
generally at about 0.5 percent. (For a 30-foot-long house, the
low end of the gutter should be about 0.15 feet or 1.8 inches
lower than the high end of the gutter.) Check your gutters during
the fall and winter to be sure they are not clogged by leaves,
snow, or ice.
Downspouts take the concentrated flow of water from the roof
gutters and discharge it onto the ground. At a minimum, the
downspout should discharge onto a splash block to prevent the
concentrated flow from gouging a gully or collecting along a
foundation. The splash block absorbs some of the energy of the
falling water and spreads it out so that it is less likely to
erode the yard. Soil may be washing away at the end of the splash
block. One solution is to attach flexible perforated plastic
tubing to the end of the downspout. This tubing is designed
to stay rolled up during dry weather. During a rain, flow from
the downspout will automatically force the tubing to unroll,
and water will be distributed through the holes in the extended
tubing. Rigid pipe also can be used, but it needs to be moved
frequently to avoid killing the grass.
Draining Swimming Pools
Improperly draining a swimming pool can contaminate nearby
streams and ponds. The chlorine, acid, and other chemicals associated
with pool maintenance can be hazardous to aquatic life. Before
draining your pool, check with your local health department
for any regulations. Start by letting the water in your pool
sit for several days to let the chemicals evaporate. Don’t
add more! After several days, test your water, and if it still
contains noticeable levels of chlorine, pool acid, or other
hazardous chemicals, drain the pool water into the sanitary
sewage system. Regardless of the test results, never drain pool
water directly into a stormwater system or stream. If chemicals
are at safe levels for groundwater discharge, then drain the
pool onto a grassed area of your property. Make sure that the
pool water does not create a drainage problem for yourself or
your neighbors.
Flooding and Storm Drainage Easements
A normal storm drainage system is sized to handle a “10-year
storm” event (10 percent chance of occurrence in any one
year). Major drainageways are designed to handle a “100-year
storm.” Occasionally high-intensity storms will exceed
the “10-year storm” event (5 to 5 1/2 inches in 24
hours), causing pipes and channels to overflow, but unless the
“100-year storm” is exceeded (about 7 1/2 to 8 inches
of rain in 24 hours), house flooding should not occur. Drainage
easements may be recorded on your property if a storm sewer
pipe, paved ditch, or drainage swale runs through your lot.
These easements are for surface drainage as well as underground
storm sewer systems. (Underground pipes and surface systems
are generally designed to carry a “10-year storm”
event.) When storms greater than this occur, the overflow stormwater
is carried on the surface. The surface swales are designed to
carry additional flow during large storms and help prevent dwelling
flooding. The easements are recorded to give you notice that
this is where stormwater runoff is intended to flow and that
you should not construct anything in the easement to interfere
with that flow. The easement gives right of access for inspection
and repair of the storm sewer system. Any construction or grading
within these easements that will interfere with maintenance
of underground systems or interfere with surface drainage is
not allowed. Fences can generally be installed in easements,
provided they do not interfere with the intended use of the
easement.
Many house lots are partially in the 100-year flood plain.
This is the area that would normally be flooded by a major storm
having a 1 percent probability of occurring in any one year.
Expect such an area to occasionally flood. These lands are good
for gardening and other uses that do not interfere with the
intended purpose of the flood plain. You must receive approval
for construction activities occurring in the 100-year flood
plain. You may be asked to sign a “Hold Harmless”
agreement, agreeing that this will be done at your risk.
Underground Drainage Systems
If surface diversion and regrading methods don’t solve
your drainage problem, you may want to construct an underground
drainage system. The most common type is an underground drain
pipe — perforated pipe in the bottom of a gravel-filled
trench. The pipe must drain downhill to a waterway, storm sewer,
or other outlet. The trench is lined with a filter fabric to
prevent the soil particles from plugging up the gravel filter
and pipe.
You can also drain surface water from your backyard with a
catch basin placed at a low spot. It is connected to a subsurface
pipe that carries the runoff to a waterway or a storm sewer.
Dry wells may work if the soil is very permeable and can absorb
a large amount of water quickly. If correctly built, dry wells
will bypass impermeable soil layers to better drained soil layers
below.
Return to Index at top of page
Houses constructed in areas without a connection to a sanitary
sewer system will have an individual subsurface sewage disposal
system. Recent advances in wastewater treatment technology and
changes to Virginia’s standards have offered a number of
new sewage disposal systems types, including low pressure dosing,
drip irrigation, spray irrigation, elevated sand mounds, alternative
discharging sewage treatment systems, and others. However, by
far the most common type of private sewage treatment and disposal
system is the conventional septic tank and drainfield system.
The purpose of a septic sewage disposal system is to carry
waste away from the house. A septic system allows the solids
to settle within a tank and the wastewater to drain to a drainfield
and be absorbed by the subsurface soils. Proper treatment and
disposal of sewage from a septic tank and drainfield system
requires that the soil be suitable to treat and dispose of large
quantities of wastewater before it reaches the groundwater.
Soils must undergo a very careful physical evaluation and/or
testing prior to health department approval in Virginia. One
commonly used test is referred to as the “perc” test
— a test of the soil’s ability to percolate, or pass,
water through it. The proposed system’s location is equally
important to avoid contamination of wells, drainageways, ponds,
or streams. Contact your local health department for more detailed
information on your system and the soils that your system relies
on for proper treatment and disposal of sewage.
Over time, the septic drainfield absorbs hundreds of thousands
of gallons of sewage effluent and will last many years if properly
maintained. A malfunction of a septic system may be expensive
and offensive, potentially resulting in a backup of sewage in
the toilets and drains of your house, sewage effluent ponding
on the surface of your drainfield, or both. Health risks to
humans caused by direct exposure to improperly treated sewage
are numerous. It is important to take care of your sewage disposal
system to prevent serious diseases, save on the astronomical
costs associated with improper maintenance, and prevent further
contamination of surface water and groundwater.
Drainfield systems constructed in the past decade generally
have a designated repair area. The intended repair area should
be reserved for this purpose only. No alterations should be
made that would alter the soil’s suitability to be used
for sewage disposal.
Plantings
A good vegetative cover should be maintained over the system.
It is important to protect the surface from any erosion since
the drainfield lines are often within 2 feet of the ground surface.
Herbaceous, shallow-rooted plants such as flowering perennials
and annuals, turfgrass, and many groundcovers are unlikely to
damage the lines. Roots from nearby trees or shrubs may clog
and damage your drain lines. Do not double dig or be too enthusiastic
in tilling the soil, given that the lines are within 2 feet
of the ground surface.
Practice Water Conservation
Household water use directly controls how quickly waste travels
through the system. Too much water moving too fast through the
septic system does not give the helpful bacteria time to break
down the solids. This is why it is important to repair dripping
faucets and leaking toilets, run washing machines and dishwashers
only when full, avoid long showers, and install water saving
features in faucets, showerheads, and toilets.
Control What Goes Down the Drain
Controlling what goes into the water that enters the septic
system is just as important as reducing the quantity of water
that flows into the system. A septic system is dependent on
a balance of “good” bacteria and solids to work properly.
Because kitchen disposals don’t “digest” what
food they grind up, they are not recommended if your house is
on a septic system. Avoid using excessive amounts of chlorine
bleach and other chemicals. They will not only take care of
the job at hand but will wipe out the helpful bacteria in your
system which are vital for breaking down waste. Non-degradables
such as grease, disposable diapers, and plastics, and chemicals
such as gasoline, oil, paint, paint thinner, pesticides, and
antifreeze should be kept out of your septic system.
Surface Drainage
All new drainfield sites are selected because of their good
natural internal soil drainage and good surface drainage. All
yard and downspout drainage, as well as your sump pump, should
be diverted away from or around the drainfield. Correct any
depressions in the drainfield where surface water might collect.
Traffic over the System
Do not allow any heavy vehicles or equipment to drive over
the drainfield, especially during wet weather. The weight of
the equipment may compact the soil and damage the network of
drain pipes. No paved areas should be constructed over septic
drainfields. Small-riding lawn mowers are okay to use on the
drainfield.
Cleaning
Households within the Chesapeake Bay Preservation Act geographic
area are required to have their septic systems pumped every
five years by a licensed pumper and hauler. Pumping your septic
tank every three to five years greatly reduces the need for
costly repairs and may enhance the life of the sewage disposal
system. Frequent pumping will reduce the accumulation of solids
and grease in the drainfield, a common cause for failure.
Contact your local health department for recommendations on
maintenance, cleaning, and alterations. Many counties now have
mandatory pump-out requirements.
Alternatives to traditional septic systems such as constructed
wetlands are being explored in parts of Virginia. For more information,
contact your local health department, the USDA Natural Resources
Conservation Service or the National Small Flows Clearinghouse.
Return to Index at top of page
If your home is on a private well system, you are solely responsible
for monitoring the quality of the water. For the health of your
family and the value of your property, pay attention to your
water quality. Water that appears clean and clear may include
potentially harmful materials. Different well types and their
age require different levels of monitoring.
The following are some signs of problems with well water.
- Members of your household have reoccurring gastrointestinal
problems. Test your water for coliform bacteria, nitrate,
and sulfate.
- Your household plumbing contains lead pipes, fittings, or
solder joints. Test for pH, lead, copper, cadmium, zinc, and
corrosion.
- Water has an objectionable taste or smell. Test for sulfur
or iron.
Test your well annually for the following.
- Total coliform bacteria (found naturally in digestive tract
of all birds and mammals; presence of unsanitary conditions
and the possibility of pathogenic microorganisms)
- Nitrates (found naturally in food, plants, water, and soil
but greatly enhanced by fertilizers and septic system effluent;
high levels are particularly harmful to expectant mothers
and newborn infants)
- pH (a measure of how acidic or alkaline a substance is;
extremes may corrode household plumbing)
- Total dissolved solids (concentration of dissolved materials
in your water is referred to as total dissolved solids)
- Pesticides
- Lead
In addition, test for contaminants that you are likely to encounter.
Based on the surrounding land uses, test for fertilizer and
pesticide contamination. It is important to keep records of
tests and results; this will enable you to identify changes
in water quality due to contamination or deterioration of the
system. Routine testing is the only way to assure that your
water supply is safe. It is recommended that you test your well
annually.
|
