WELL TYPES AND CONSTRUCTION - A well is a hole drilled into the ground to access water contained in an aquifer. A pipe and a pump are used to pull water out of the ground, and a screen filters out unwanted particles that could clog the pipe. Wells come in different shapes and sizes, depending on the type of material the well is drilled into and how much water is being pumped out. More than 42 million people in the United States use individual or private wells to supply water for their families. All private well construction is based on establishing the right location for the well, sizing the system correctly and choosing the proper construction techniques. Proper well construction is key to operating and maintaining a well.

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Well Types And Construction

WHAT IS A WELL?

THE GROUNDWATER FOUNDATION

Basically, a well is a hole drilled into the ground to access water contained in an aquifer.

A pipe and a pump are used to pull water out of the ground, and a screen filters out unwanted particles that could clog the pipe.

Wells come in different shapes and sizes, depending on the type of material the well is drilled into and how much water is being pumped out.

More than 42 million people in the United States use individual or private wells to supply water for their families.

THREE BASIC TYPES OF WELLS

·         Bored or shallow wells are usually bored into an unconfined water source, generally found at depths of 100 feet or less.

·        Consolidated or rock wells are drilled into a formation consisting entirely of a natural rock formation that contains no soil and does not collapse. Their average depth is about 250 feet.

·        Unconsolidated or sand wells are drilled into a formation consisting of soil, sand, gravel or clay material that collapses upon itself.

WELL CONSTRUCTION

All private well construction is based on establishing the right location for the well, sizing the system correctly and choosing the proper construction techniques.

Only professional water well contractors should install wells. They are familiar with the hydrology in an area and all local codes and regulations.

Proper well construction is key to operating and maintaining a well.

A well is composed of many components. The most important materials used include:

·         Casing is used to maintain an open access in the earth while not allowing any entrance or leakage into the well from the surrounding formations. The most popular materials used for casing are black steel, galvanized steel, PVC pipe and concrete pipe.

·         Grout is a sealant that is used to fill in the spaces around the outside of the well. It protects the well against the intrusion of contaminants. A grout mixture can be made of cement, bentonite, or concrete (each used separately).

·         Screen keeps sand and gravel out of the well while allowing groundwater and water from formations to enter into the well. Screen is available in many materials, the most popular being stainless steel and slotted PVC pipe. Screen is used when wells are drilled into unconsolidated materials.

·         Gravel pack is placed around the outside of the screen to prevent sand from entering the well or clogging the screen and to stabilize the well assembly.

WELL CONTAMINATION

A well can easily be contaminated if it is not properly constructed or if toxic materials are released into the well.

Toxic material spilled or dumped near a well can leach into the aquifer and contaminate the groundwater drawn from that well.

Contaminated wells used for drinking water are especially dangerous.

Wells can be tested to see what chemicals, pathogens and other contaminants may be in the well and if they are present in dangerous quantities.

THINGS YOU CAN DO TO PROTECT YOUR GROUNDWATER AND WATER WELL:

·          Maintain your well

·          Keep hazardous materials away from your well

·          Install a well cap

·          Use caution around your well

·          Conserve water

·          Learn more about well testing.

Special thanks to the Water Systems Council for contributing information contained in this article.

THE GROUNDWATER FOUNDATION CONNECTS PEOPLE, BUSINESSES, AND COMMUNITIES THROUGH LOCAL GROUNDWATER EDUCATION AND ACTION, MAKING US ALL PART OF THE SOLUTION FOR CLEAN, SUSTAINABLE GROUNDWATER.

We all rely on groundwater in some way, and groundwater relies on us to protect it.
Learn more, get involved - collectively we make a difference!

https://www.groundwater.org/get-informed/basics/wells.html

NITRATE IN WELL WATER - You cannot taste, see, or smell nitrate in your water. Nitrate is a compound that occurs naturally and also has many human-made sources. Nitrate is in some lakes, rivers, and groundwater. Some groundwater has nitrate concentrations that present a health risk - especially for babies. Consuming too much nitrate can affect how blood carries oxygen and can cause methemoglobinemia (also known as blue baby syndrome). Bottle-fed babies under six months old are at the highest risk of getting methemoglobinemia. Methemoglobinemia can cause skin to turn a bluish color and, left untreated, can result in serious illness or death.

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Nitrate in Well Water

Minnesota Department of Health
Well Management Program

Nitrate is a compound that occurs naturally and also has many human-made sources.

Nitrate is in some lakes, rivers, and groundwater in Minnesota.

When nitrate is found in Minnesota groundwater, it is usually at very low concentrations.

However, some groundwater has nitrate concentrations that present a health risk - especially for babies.

You cannot taste, see, or smell nitrate in your water.

Safe Level

Drinking water with concentrations of nitrate (measured as nitrate-nitrogen) below 10 milligrams of nitrate per liter of water (mg/L) is considered safe for everyone in your family.

10 mg/L is the U.S. Environmental Protection Agency standard for nitrate in drinking water for public water supplies.

Health Risks

Consuming too much nitrate can affect how blood carries oxygen and can cause methemoglobinemia (also known as blue baby syndrome).

Bottle-fed babies under six months old are at the highest risk of getting methemoglobinemia.

Methemoglobinemia can cause skin to turn a bluish color and, left untreated, can result in serious illness or death.

The following conditions may also put people at higher risk of developing nitrate-induced methemoglobinemia: anemia, cardiovascular disease, lung disease, sepsis, glucose-6-phosphate-dehydrogenase deficiency, and some metabolic problems.

Only recently has scientific evidence emerged to assess the health impacts of drinking water with high nitrate on adults.

A growing body of literature indicates potential associations between nitrate/nitrite exposure and other health effects such as increased heart rate, nausea, headaches, and abdominal cramps. 
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Some studies also suggest an increased risk of cancer, especially gastric cancer, associated with dietary nitrate/nitrite exposure, but there is not yet scientific consensus on this question.

Test Your Well Water

Test for nitrate every other year. You should also have your water tested for nitrate if you planning on becoming pregnant or if infants will be using the water.

You are responsible for keeping your well water safe and testing it as needed.

MDH recommends you use an accredited laboratory to test your water. 
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Contact an accredited laboratory to get sample containers and instructions, or ask your county environmental or public health services if they provide well testing services (Accredited Labs in Minnesota Accepting Samples from Private Well Owners [PDF]).

Go to Well Testing, Results, and Options to learn more about testing well water.

MDH may recommend you test for additional contaminants based on where you live.

Prevent Contamination

·           Keep nitrate sources away from your well. Sources may include fertilizer, septic systems, and animal waste.

·           Construct your well in a safe spot.

·          Regularly inspect your well for damage. Contact a licensed well contractor if your well is damaged (Licensed Well and Boring Contractor Directory).

Wells Vulnerable to Nitrate

·           Shallow wells.

·           Wells in sand aquifers.

·           Dug wells with casings that are not watertight.

·           Wells with damaged or leaking casing or fittings.

Address Contamination

Drinking water with concentrations of nitrate above 10 mg/L can cause immediate health problems.

If nitrate is detected in your water at concentrations above 10 mg/L, follow these steps:

·          Get your drinking water from a safe alternative source, such as bottled water.

·          Make sure babies under six months old do not drink the well water.

·          Do not try to boil nitrate out of the water. Boiling will make nitrate more concentrated.

·          Have a licensed well contractor inspect your well.

·          Find and get rid of any potential sources of nitrate contamination. The Protecting Your Well webpage can help you identify sources to check.

·          Home water treatment may be an option if you meet these three criteria:

1.    You took steps to reduce or eliminate all potential sources of nitrate on your property;

2.    A licensed well contractor inspected your well and completed any needed repairs; and

3.    No babies under six months old drink the water (a safety precaution in the event the water treatment fails).

See the Home Water Treatment webpage or contact MDH for guidance.

How Nitrate Gets Into Groundwater

Nitrate occurs naturally and at safe and healthy levels in some foods (such as spinach and carrots) and comes from natural processes, such as plant decay.

Nitrate is in many fertilizers used on yards, golf courses, and crops. Other sources of nitrate include discharge from sewage systems and animal wastes.

Natural levels of nitrate in Minnesota groundwater are usually quite low (less than 3 milligrams per liter [mg/L]).

However, where sources of nitrate such as fertilizers, animal wastes, or human sewage are concentrated near the ground surface, nitrate may seep down and contaminate the groundwater.

High levels of nitrate in water can be a result of runoff or leakage from fertilized soil, wastewater, landfills, animal feedlots, septic systems, or urban drainage.

It can be difficult to pinpoint where the nitrate in drinking water comes from because there are many possibilities.

Nitrate in Minnesota Water

About 4 percent of new wells have nitrate concentrations above 3 mg/L in Minnesota. While 3 mg/L is less than the EPA standard, it suggests human-made sources of nitrate have contaminated the water and the level could increase over time.

Most concentrations above 3 mg/L are in central and southeastern Minnesota. Concentrations above 10 mg/L are mainly in central and southwestern Minnesota.

The Minnesota Department of Agriculture  Township Testing Program found that over 10 percent of the private wells sampled in some townships in southwestern, southeastern, central, and north-central Minnesota have nitrate levels above 10 mg/L.

Should I test my well water for anything besides lead?

Yes. Both natural sources and human activities can contaminate well water and cause short-term or long-term health effects.

Testing your well water is the only way to detect most of the common contaminants in Minnesota groundwater; you cannot taste, see, or smell most contaminants. Minnesota Department of Health recommends testing for:

·          Coliform bacteria every year and any time the water changes in taste, odor, or appearance. Coliform bacteria can indicate that disease-causing microorganisms may be in your water.

·         Arsenic at least once. About 40 percent of wells in Minnesota have arsenic in the water.

Drinking water with arsenic in it for a long time can contribute to reduced intelligence in children and increased risks of cancer, diabetes, heart disease, and skin problems.
Lead at least once. The well and water system may have parts that have lead in them, and that lead can get into drinking water. Lead can damage the brain, kidneys, and nervous system. Lead can also slow development or cause learning, behavior, and hearing problems.
Manganese before a baby drinks the water. High levels of manganese can cause problems with memory, attention, and motor skills. It can also cause learning and behavior problems in infants and children.
Other contaminants sometimes occur in private water systems, but less often than the contaminants listed above. Consider testing for:

·          Volatile organic chemicals if the well is near fuel tanks or a commercial or industrial area.

·         Agricultural chemicals commonly used in the area if the well is shallow and is near cropped fields or handling areas for agricultural chemicals or is in an area of geologic sensitivity (such as fractured limestone).

·         Fluoride if children or teenagers drink the water.

Minnesota Department of Health

https://www.health.state.mn.us/communities/environment/water/wells/waterquality/nitrate.html

UNDERSTANDING YOUR WELL - Well water is drawn directly from the immediate groundwater surrounding it. Groundwater is affected by all sources of contamination mentioned earlier. Well caps are susceptible to lightning strikes. Septic systems recharge groundwater through normal use. Malfunctioning septic systems can contaminate the immediate groundwater with untreated If any of the tests are reported as over the MCL, you should come to the Health Department to inquire about next steps. Conductivity is a measure of how well your water carries an electrical current. Conductivity is not a "contaminant" and will not cause illness, though it can be indicative of minerals.

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Understanding Your Well

Health Department, Nantucket, MA

The Anatomy of a Well:

·         Well Cap: Prevent insects, debris, and small animals from entering the well

·         Well Casing: hollow tube that encases the well and maintains structural integrity

·         Distribution Line: Water supply line to the dwelling

·         Bentonite Grout: Seals well in place. Prevents water intrusion

·         Drop Pipe: actual water supply to home

·         Pump: Draws water through filtering screen, up drop pipe, through Distribution line, into home

·         Well Screen: filters out fine material from groundwater

·         Gravel Pack: Provide large particle filtration before groundwater enters well screen

Well Functions:

·         Well water is drawn directly from the immediate groundwater surrounding it

·         Groundwater is affected by all sources of contamination mentioned earlier

·         Well caps are susceptible to lightning strikes.

·         Septic systems recharge groundwater through normal use.

·         Malfunctioning septic systems can contaminate the immediate groundwater with untreated effluent.

Understanding your water quality report

·         Visit the water contamination page to learn about contaminants over the MCL (maximum contamination limit)

·         If any of the tests are reported as over the MCL, you should come to the Health Department to inquire about next steps.

What does conductivity mean?

·         Conductivity is a measure of how well your water carries an electrical current.

·         Conductivity is not a "contaminant" and will not cause illness, though it can be indicative of minerals that can.

·         For example, if you have high salinity/sodium levels, you probably will also have high conductivity.

What does the pH mean?

·          pH is a measure of the hydrogen ions in solution.

·          Any pH less than 6.5 or greater than 8.5 is considered corrosive.

·         The primary concern is of lead and copper from pipes being dissolved in corrosive drinking water.

·          If your home was built before 1980, and your well water report shows that your water is corrosive, it is recommended that you look into re-plumbing your home.

 

https://www.nantucket-ma.gov/937/Understanding-Your-Well