Home inspections are important to have done on every home being bought or
If your family gets drinking water from a private well, do you know if
your water is safe to drink? What health risks could you and your family
face? Where can you go for help or advice? EPA regulates public water
systems; it does not have the authority to
regulate private drinking water wells. Approximately 15 percent of Americans
rely on their own private drinking water supplies, and these supplies
are not subject to EPA standards, although some state and local governments
do set rules to protect users of these wells. Unlike public drinking water
systems serving many people, they do not have experts regularly checking
the water’s source and its quality before it is sent to the tap.
These households must take special precautions to ensure the protection
and maintenance of their drinking water supplies.
Private Water Wells
There are three types of private drinking water wells: dug, driven, and
drilled. Proper well construction and continued maintenance are keys to the safety
of your water supply. Your state water-well contractor licensing agency,
local health department, or local water system professional can provide
information on well construction. The well should be located so rainwater flows away from it. Rainwater
can pick up harmful bacteria and chemicals on the land’s surface.
If this water pools near your well, it can seep into it, potentially causing
health problems. Water-well drillers and pump-well installers are listed in your local
phone directory. The contractor should be bonded and insured. Make certain
your ground water contractor is registered or licensed in your state,
if required. If your state does not have a licensing/registration program
contact the National Ground Water Association. They have a voluntary certification
program for contractors. (In fact, some states use the Association’s
exams as their test for licensing.) For a list of certified contractors
in your state contact the Association at (614) 898-7791 or (800) 551-7379.
There is no cost for mailing or faxing the list to you.
keep your well safe, you must be sure possible sources of contamination
are not close by. Experts suggest the following distances as a minimum
for protection — farther is better (see
graphic on the right):
- Septic Tanks, 50 feet
- Livestock yards, Silos, Septic Leach Fields, 50 feet
- Patroleum Tanks, Liquid-Tight Manure Storage and Fertilizer Storage
and Handling, 100 feet
- Manure Stacks, 250 feet
Many homeowners tend to forget the value of good maintenance until problems
reach crisis levels. That can be expensive. It’s better to maintain
your well, find problems early, and correct them to protect your well’s
performance. Keep up-to-date records of well installation and repairs
plus pumping and water tests. Such records can help spot changes and possible
problems with your water system. If you have problems, ask a local expert
to check your well construction and maintenance records. He or she can
see if your system is okay or needs work.
Protect your own well area. Be careful about storage and disposal of
household and lawn care chemicals and wastes. Good farmers and gardeners
minimize the use of fertilizers and pesticides. Take steps to reduce erosion
and prevent surface water runoff. Regularly check underground storage
tanks that hold home heating oil, diesel, or gasoline. Make sure your
well is protected from the wastes of livestock, pets, and wildlife.
Dug wells are holes in the ground dug by shovel or backhoe. Historically,
a dug well was excavated below the groundwater table until incoming water
exceeded the digger’s bailing rate. The well was then lined (cased)
with stones, brick, tile, or other material to prevent collapse. It was
covered with a cap of wood, stone, or concrete. Since it is so difficult
to dig beneath the ground water table, dug wells are not very deep. Typically,
they are only 10 to 30 feet deep. Being so shallow, dug wells have the
highest risk of becoming contaminated.To minimize the likelihood of contamination,
your dug well should have certain features. These features help to prevent
contaminants from traveling along the
outside of the casing or through
the casing and into the well.
Dug Well Construction Features
- The well should be cased with a watertight material (for example,
tongue-and-groove precast concrete) and a cement grout or bentoniteclay
sealant poured along the outside of the casing to the top of the well.
- The well should be covered by a concrete curband cap that stands about
a foot above the ground.
- The land surface around the well should be mounded so that surface
water runs away from the well and is not allowed to pond around the
outside of the wellhead.
- Ideally, the pump for your well should be inside your home or in a
separate pump house, rather than in a pit next to the well.
Land activities around a dug well can also contaminate it.
While dug wells have been used as a household water supply source for
many years, most are “relics” of older homes, dug before drilling
equipment was readily available or when drilling was considered too expensive.
If you have a dug well on your property and are using it for drinking
water, check to make sure it is properly covered and sealed. Another problem
relating to the shallowness of a dug well is that it may go dry during
a drought when the ground water table drops.
Like dug wells, driven wells pull water from the
water-saturated zone above the bedrock. Driven wells can be deeper than
dug wells. They are typically 30 to 50 feet deep and are usually
located in areas with thick sand and gravel deposits where the ground
water table is within 15 feet of the ground’s surface. In the proper
geologic setting, driven wells can be easy and relatively inexpensive
to install. Although deeper than dug wells, driven wells are still
relatively shallow and have a moderate-to-high risk of contamination
from nearby land activities.
Driven Well Construction Features
- Assembled lengths of two inches to three inches diameter metal pipes
are driven into the ground. Ascreened “well point” located
at the end of the pipe helps drive the pipe through the sand and gravel.
The screen allows water to enter the well and filters out sediment.
- The pump for the well is in one of two places: on top ofthe well or
in the house. An access pit is usually dug around the well down to the
frost line and a water dis-charge pipe to the house is joined to the
well pipe with a fitting.
- The well and pit are capped with the same kind of large-diameter concrete
tile used for a dug well. The access pit may be cased with pre-cast
To minimize this risk, the well cover should be a tight-fitting concrete
curb and cap with no cracks and should sit about a foot above the ground.
Slope the ground away from the well so that surface water will not pond
around the well. If there’s a pit above the well, either to hold
the pump or to access the fitting, you may also be able to pour a grout
sealant along the outside of the well pipe. Protecting the water quality
requires that you maintain proper well construction and monitor your activities
around the well. It is also important to follow the same land use precautions
around the driven well as described under dug wells.
Drilled wells penetrate about 100-400 feet into the bedrock. Where you
find bedrock at the surface, it is commonly called ledge. To serve as
a water supply, a drilled well must intersect bedrock fractures containing
Drilled Well Construction Features
- The casing is usually metal or plastic pipe, six inches in diameter
that extends into the bedrock to prevent shallow ground water from entering
the well. By law, the casing has to extend at least 18 feet into the
ground, with at least five feet extending into the bedrock. The casing
should also extend a foot or two above the ground’s surface. A
sealant, such as cement grout or bentonite clay, should be poured along
the outside of the casing to the top of the well. The well is capped
to prevent surface water from entering the well.
- Submersible pumps, located near the bottom of the well, are most commonly
used in drilled wells. Wells with a shallow water table may feature
a jet pump located inside the home. Pumps require special wiring and
electrical service. Well pumps should be installed and serviced by a
qualified professional registered with your state.
- Most modern drilled wells incorporate a pitless adapter designed to
provide a sanitary seal at the point where the discharge water line
leaves the well to enter your home. The device attaches directly to
the casing below the frost line and provides a watertight subsurface
connection, protecting the well from frost and contamination.
- Older drilled wells may lack some of these sanitary features. The
well pipe used was oftene ight-, 10- or 12- inches in diameter, and
covered with a concrete well cap either at or below the ground’s
surface. This outmoded type of construction does not provide the same
degree of protection from surface contamination. Also, older wells may
not have a pitless adapter to provide a seal at the point of discharge
from the well.
Hydrofracting A Drilled Well
Hydrofracting is a process that applies water or air under pressure
into your well to open up existing fractures near your well and can even
create new ones. Often this can increase the yield of your well. This
process can be applied to new wells with insufficient yield and to improve
the quantity of older wells.
How can I test the quality of my private drinking
Consider testing your well for pesticides, organic chemicals, and
heavy metals before you use it for the first time. Test private water
supplies annually for nitrate and coliform bacteria to detect contamination
problems early. Test them more frequently if you suspect a problem.
Be aware of activities in your watershed that may affect the water
quality of your well, especially if you live in an unsewered area.
What You Can Do...
The first step
to protect your health and the health of your family is learning
about what may pollute your source of drinking water. Potential
contamination may occur naturally, or as a result of human activity.
What are Some Naturally Occurring Sources of Pollution?
- Microorganisms: Bacteria, viruses, parasites
and other microorganisms are sometimes found in water. Shallow
wells — those with water close to ground level — are
at most risk. Runoff, or water flowing over the land surface,
may pick up these pollutants from wildlife and soils. This is
often the case after flooding. Some of these organisms can cause
a variety of illnesses. Symptoms include nausea and diarrhea.
These can occur shortly after drinking contaminated water. The
effects could be short-term yet severe (similar to food poisoning)
or might recur frequently or develop slowly over a long time.
- Radionuclides: Radionuclides are radioactive
elements such as uranium and radium. They may be present in underlying
rock and ground water
- Radon: Radon is a gas that
is a natural product of the breakdown of uranium in the soil —
can also pose a threat. Radon is most dangerous when inhaled and
contributes to lung cancer. Although soil is the primary source,
using household water containing Radon contributes to elevated
indoor Radon levels. Radon is less dangerous when consumed in
water, but remains a risk to health.
- Nitrates and Nitrites: Although high nitrate
levels are usually due to human activities (see below), they may
be found naturally in ground water. They come from the breakdown
of nitrogen compounds in the soil. Flowing ground water picks
them up from the soil. Drinking large amounts of nitrates and
nitrites is particularly threatening to infants (for example,
when mixed in formula).
- Heavy Metals: Underground rocks and soils
may contain arsenic, cadmium, chromium, lead, and selenium. However,
these contaminants are not often found in household wells at dangerous
levels from natural sources.
- Fluoride: Fluoride is helpful in dental health,
so many water systems add small amounts to drinking water. However,
excessive consumption of naturally occurring fluoride can damage
bone tissue. High levels of fluoride occur naturally in some areas.
It may discolor teeth, but this is not a health risk.
What Human Activities Can Pollute Ground Water?
Septic tanks are designed to have a “leach field” around them an area where
wastewater flows out of the tank. This wastewater can also move into the
- Bacteria and Nitrates: These pollutants are found
in human and animal wastes. Septic tanks can cause bacterial and
nitrate pollution. So can large numbers of farm animals. Both
septic systems and animal manures must be carefully managed to
prevent pollution. Sanitary landfills and garbage dumps are also
sources. Children and some adults are at extra risk when exposed
to water-born bacteria. These include the elderly and people whose
immune systems are weak due to AIDS or treatments for cancer.
Fertilizers can add to nitrate problems. Nitrates cause a health
threat in very young infants called “blue baby” syndrome.
This condition disrupts oxygen flow in the blood.
- Concentrated Animal Feeding Operations (CAFOs):
The number of CAFOs, often called “factory farms,”
is growing. On these farms thousands of animals are raised in
a small space. The large amounts of animal wastes/manures from
these farms can threaten water supplies. Strict and careful manure
management is needed to prevent pathogen and nutrient problems.
Salts from high levels of manures can also pollute ground water.
- Heavy Metals: Activities such as mining and
construction can release large amounts of heavy metals into nearby
ground water sources. Some older fruit orchards may contain high
levels of arsenic, once used as a pesticide. At high levels, these
metals pose a health risk.
- Fertilizers and Pesticides: Farmers use fertilizers
and pesticides to promote growth and reduce insect damage. These
products are also used on golf courses and suburban lawns and
gardens. The chemicals in these products may end up in ground
water. Such pollution depends on the types and amounts of chemicals
used and how they are applied. Local environmental conditions
(soil types, seasonal snow and rainfall) also affect this pollution.
Many fertilizers contain forms of nitrogen that can break down
into harmful nitrates. This could add to other sources of nitrates
mentioned above. Some underground agricultural drainage systems
collect fertilizers and pesticides. This polluted water can pose
problems to ground water and local streams and rivers. In addition,
chemicals used to treat buildings and homes for termites or other
pests may also pose a threat. Again, the possibility of problems
depends on the amount and kind of chemicals. The types of soil
and the amount of water moving through the soil also play a role.
- Industrial Products and Wastes: Many harmful
chemicals are used widely in local business and industry. These
can become drinking water pollutants if not well managed. The
most common sources of such problems are:
- Local Businesses: These include nearby
factories, industrial plants, and even small businesses such
as gas stations and dry cleaners. All handle a variety of
hazardous chemicals that need careful management. Spills and
improper disposal of these chemicals or of industrial wastes
can threaten ground water supplies.
- Leaking Underground Tanks & Piping:
Petroleum products, chemicals, and wastes stored in underground
storage tanks and pipes may end up in the ground water. Tanks
and piping leak if they are constructed or installed improperly.
Steel tanks and piping corrode with age. Tanks are often found
on farms. The possibility of leaking tanks is great on old,
abandoned farm sites. Farm tanks are exempt from the EPA rules
for petroleum and chemical tanks.
- Landfills and Waste Dumps: Modern landfills
are designed to contain any leaking liquids. But floods can
carry them over the barriers. Older dumpsites may have a wide
variety of pollutants that can seep into ground water.
- Household Wastes: Improper disposal of many
common products can pollute ground water. These include cleaning
solvents, used motor oil, paints, and paint thinners. Even soaps
and detergents can harm drinking water. These are often a problem
from faulty septic tanks and septic leaching fields.
- Lead & Copper: Household plumbing materials
are the most common source of lead and copper in home drinking
water. Corrosive water may cause metals in pipes or soldered joints
to leach into your tap water. Your water’s acidity or alkalinity
(often measured as pH) greatly affects corrosion. Temperature
and mineral content also affect how corrosive it is. They are
often used in pipes, solder, or plumbing fixtures. Lead can cause
serious damage to the brain, kidneys, nervous system, and red
blood cells. The age of plumbing materials — in particular,
copper pipes soldered with lead — is also important. Even
in relatively low amounts these metals can be harmful. EPA rules
under the Safe Drinking Water Act limit lead in drinking water
to 15 parts per billion. Since 1988 the Act only allows “lead
free” pipe, solder, and flux in drinking water systems.
The law covers both new installations and repairs of plumbing.
Private, individual wells are the responsibility of the homeowner.
To help protect your well, here are some steps you can take:
Have your water tested periodically. It is recommended that
water be tested every year for total coliform bacteria, nitrates, total
dissolved solids, and pH levels. If you suspect other contaminants,
test for those. Always use a state certified laboratory that conducts
drinking water tests. Since these can be expensive, spend some time
identifying potential problems.
Testing more than once a year may be warranted in special situations:
- someone in your household is pregnant
- there are unexplained illnesses in
- your neighbors find a dangerous contaminant
in their water
- you note a change in water taste, odor,
color or clarity
- there is a spill of chemicals or fuels
into or near your well
- when you replace or repair any part
of your well system
Identify potential problems as the first step to safeguarding your
drinking water. The best way to start is to consult a local expert,
someone that knows your area, such as the local health department,
agricultural extension agent, a nearby public water system, or a geologist
at a local university.
Be aware of your surroundings. As you drive around your community,
take note of new construction. Check the local newspaper for articles
about new construction in your area. Check the paper or call your local planning or zoning commission for
announcements about hearings or zoning appeals on development or industrial
projects that could possibly affect your water.
these hearings, ask questions about how your water source is being
protected, and don't be satisfied with general answers. Make statements
like "If you build this landfill, (just an example) what will you
do to ensure that my water will be protected." See how quickly they
answer and provide specifics about what plans have been made to
specifically address that issue.
Identify Potential Problem Sources
To start your search for potential problems, begin close to home.
Do a survey around your well:
- is there livestock nearby?
- are pesticides being used on nearby agricultural crops or nurseries?
- do you use lawn fertilizers near the well?
- is your well "downstream" from your own or a neighbor's septic
- is your well located near a road that is frequently salted
or sprayed with de-icers during winter months?
- do you or your neighbors dispose of household wastes or used
motor oil in the backyard, even in small amounts?
If any of these items apply, it may be best to have your water
tested and talk to your local public health department or agricultural
extension agent to find way to change some of the practices which
can affect your private well.
In addition to the immediate area around your well, you should
be aware of other possible sources of contamination that may already
be part of your community or may be moving into your area. Attend
any local planning or appeal hearings to find out more about the
construction of facilities that may pollute your drinking water.
Ask to see the environmental impact statement on the project. See
if underground drinking water sources has been addressed. If not,
Common Sources of Potiental Ground Water Contamination
- Animal burial areas
- Drainage fields/wells
- Animal feedlots
- Irrigation sites
- Fertilizer storage/use
- Manure spreading areas/pits, lagoons
- Pesticide storage/use
- Jewelry/metal plating
- Auto repair shops
- Medical institutions
- Car washes
- Paint shops
- Construction areas
- Photography establishments
- Cemeteries Process waste water drainage
- Dry cleaners fields/wells
- Gas stations
- Railroad tracks and yards
- Gulf courses
- Research laboratories
- Scrap and junkyards
- Storage tanks
- Asphalt plants
- Petroleum production/storage
- Chemical manufacture/storage
- Electronic manufacture
- Process waste water drainage
- Electroplaters fields/wells
- Foundries/metal fabricators
- Septage lagoons and sludge
- Machine/metalworking shops
- Storage tanks
- Mining and mine drainage
- Toxic and hazardous spills
- Wood preserving facilities
- Fuel Oil
- Septic systems, cesspools
- Furniture stripping/refinishing
- Sewer lines
- Household hazardous products
- Swimming pools (chemicals)
- Household lawns
- Hazardous waste landfills
- Recycling/reduction facilities
- Municipal incinerators
- Road deicing operations
- Municipal landfills
- Road maintenance depots
- Municipal sewer lines
- Storm water drains/basins/wells
- Open burning sites
- Transfer stations