Sign up for the latest water news and information.
Wells: Common contaminants and maintenance concerns
How do wells work, and where are they typically located?
Found primarily in rural areas, wells tap into underground pockets of water, called aquifers, and pump it into the pipes of your home for drinking, cooking, cleaning and sanitation. Wells are recharged when precipitation and water used for irrigating crops and landscapes seeps into the rock below the surface of the earth. The level of the water table—a boundary between water-saturated ground and unsaturated ground—can fluctuate due to annual rainfall patterns, droughts and the amount of water being pumped out from the aquifer.
What is the current % of well users nationwide today?
With improvements in modern technology and the advent of urban sprawl, nearly 86% of the United States now gets their water from public water supply systems. The remainder of the population (over 15 million households) gets their water from privately-owned wells.1
What is critical to know when constructing a well?
Prior to building a well, a detailed site survey must be done to ensure its long-term success and reduce health risks. The survey measures geology, water table depth, seasonal fluctuations, recharge area and rate.2 Also, some states have laws that regulate the types of wells that be constructed, how many wells can be located in a certain area, and how much water can be extracted over a certain time period. In such cases, well construction permits must be obtained before any digging can begin. All of these considerations will help determine the design and location of the well.
Each type of well construction has its own advantages and disadvantages, depending on the proposed location, water table levels and pumping capacity requirements. Local runoff patterns, and their potential for contaminating the groundwater near the well, may influence the location and design of the well too. According to the U.S. Geological Survey, water wells are typically constructed in one of three ways:
- Dug wells are excavated until the well reaches the water table. To prevent collapse and provide protection against contaminants, the well is lined with stones, bricks or tile and capped with stone, wood or concrete. Dug wells are generally less expensive to build than other wells but are more vulnerable to surface runoff contamination. Since they are relatively shallow, dug wells are also susceptible to drought and can dry up if the water table recedes below the floor of the well.
- Drilled wells are built using rotary or percussion drilling equipment. Rotary machines drill a shaft through solid rock. Percussion equipment uses a heavy bit that is attached to a cable and repeated dropped to break up rock. Drilled wells can be over a thousand feet deep and are lined with casing, which reduces the possibility of contamination.
- Driven wells are constructed by driving small-diameter pipes into water-bearing sand and gravel deposits to a depth of 30-50 feet. The bottom of the pipe is fitted with a drive-point screen, which allows water to flow up the pipe while keeping sediment out. Driven wells are relatively inexpensive to install but their shallow depth, like dug wells, makes them susceptible to contamination by surface sources.3
PROXIMITY TO POTENTIAL SOURCES OF CONTAMINATION
Potential contamination sources in the area are another factor to consider. Pollution from nearby agricultural, industrial and routine human activity can seep into your well water, drastically affecting its fitness for consumption. Sources can include:
- Leaks or spills of industrial chemicals at manufacturing facilities
- Livestock wastes
- On-site septic systems
- Contaminants in rain, snow, and dry atmospheric fallout
- Toxins leaking from graveyards
- Fertilizers and pesticides on agricultural land
- Industrial waste from underground injection wells
- Runoff of salt and other chemicals from roads and highways
- Leaky tanks or pipelines containing petroleum products4
Therefore, it is critical that a safe distance be maintained between wells and possible sources of contamination. The Centers for Disease Control and Prevention’s guidelines are:
- Septic tanks: 50 feet from well
- Livestock yards, silos, septic leach fields: 50 feet from well
- Petroleum tanks, liquid-tight manure storage and fertilizer storage and handling: 100 feet from well
- Manure stacks: 250 feet from well5
What are a well’s most common potential contaminants and health risks?
Private wells can be contaminated by a variety of sources. The EPA lists six major well water contaminants: microbiologicals, heavy metals, organic chemicals, radionuclides, fluoride and nitrates.6
Microbiological contaminants such as e. Coli bacteria occur naturally in the environment, and are found in soil and human and animal waste. Potential health effects of pathogenic bacteria can include polio, cholera, typhoid fever, dysentery, and infectious hepatitis among other illness.7
Read the following for more:
- E. coli Bacteria Explained
- Leptospirosis: Serious illness often spread through raw, contaminated wate
Heavy metals include arsenic, lead, copper, chromium, selenium and more. Heavy metals can contaminate drinking water via older, corroded plumbing lines or runoff from industrial, manufacturing and mining operations. Lead and copper contamination can also occur if the plumbing inside the household being served by the well hasn't been updated. Excess levels of heavy metals in the human body can cause damage to kidneys and liver, intestinal problems, cancer and more.8
Read the following for more:
Radionuclides, also known as radiologicals, are naturally occuring and found everywhere: the earth’s crust, food, the sun’s rays and even our DNA. Common radionuclides like uranium, radium and radon are often found in areas with granite bedrock. Other sources of exposure are the result of waste from the coal industry, the oil and gas industry, metal mining and smelting, fertilizer production and waste from nuclear power plants and some medical facilities. Released or improperly stored radioactive particles can seep into groundwater, or bind to particles of dust in the air. Long-term exposure, or brief exposure to radiologicals in high doses, is known to lead to cancer.
Read the following for more:
Fluoride is best known for its ability to reduce tooth decay and is found in almost all water. Although it is unlikely your well has fluoride levels higher than the the current enforceable drinking water standard of 4.0 mg/L,10, 11 prolonged exposure to high levels of fluoride can lead to skeletal fluorosis, a painful condition caused by fluoride buildup in the bones and joints. Excessive fluoride consumption during childhood can cause dental fluorosis, which damages the enamel and results in tooth discoloration and pitting of teeth. The EPA’s recommended guideline for protecting against dental fluorosis is 2.0 mg/L.12
Nitrates are naturally occurring compounds that can enter well water from runoff from sewage and septic systems, industrial activity, animal waste and fertilizers. Consumption of water with high nitrate levels can cause methemoglobinemia, or “blue baby disease”, a potentially fatal condition in which the blood’s oxygen-carrying capacity is reduced.13 Nitrate levels above established guidelines are also a health concern for pregnant women, developing babies, the elderly, and individuals with weakened immune systems or chronic heart, lung or blood conditions.14
According to the CDC, the top six causes of outbreaks from 1971-2010 in individual private water systems - wells were:
- Hepatitis A (virus)
- Giardia (microscopic parasite)
- Tie: Campylobacter, E. coli (bacteria)
- Shigella (bacteria)
- Tie: Cryptosporidium (microscopic parasite), Salmonella (bacteria)
- Tie: Arsenic (heavy metal), Gasoline (chemical), Nitrate, Phenol (chemical), Selenium (trace mineral, also used in manufacturing)15
Who is responsible for the water quality of a well?
While the construction of private wells may be subject to local or state ordinances, the quality of a private well’s output is the sole responsibility of the owner. The Environmental Protection Agency does not regulate private wells or provide standards for individual wells.16
According to the CDC, you should have your well tested once a year for:
- Total coliform bacteria
- Total dissolved solids
- pH levels17
The CDC also recommends having your well tested if:
- There are known problems with well water in your area
- You have experienced problems near your well (i.e., flooding, land disturbances, and nearby waste disposal sites)
- You replace or repair any part of your well system
- You notice a change in water quality (i.e., taste, color, odor)18
There are many state-certified water testing labs across the country. You can find one by calling the EPA Safe Water Drinking Hotline at (800) 426-4791, or by contacting your local health department. The EPA’s website also maintains a state-by-state listing.
In addition to periodic water testing, regular physical inspections can help you spot potential problems that might lead to contamination. To make sure your well is performing at its best, Health Canada offers the following tips:
- The well cap should be checked regularly to ensure that it is securely in place and watertight
- Joints, cracks and connections in the well casing should be sealed
- Pumps and pipes should also be checked on a regular basis
- Any changes in water quality should be investigated.
Also, it is a good idea to conduct regular visual inspections of the area immediately surrounding your well, taking into account the following:
- Have farm animals been allowed to graze around, near or upstream from your well? Does wildlife typically graze around your well? If so, consider fencing in the area around your well.
- Has any type of construction occurred in the area near your well?
- Has a new home been constructed in your area and was their septic system installed the proper distance from your well?
What if a contaminant shows up in a well water test?
By the time a test reveals that your well has contaminants, it’s possible that you have been consuming that water for some time—and should stop immediately. Make sure you have a plan in place regarding how to obtain clean water (purchasing bottled water, boiling it, disinfecting it with bleach, purification) in an emergency.20
Even better, establish a daily water treatment strategy. Address the possibility of contaminants even before testing picks them up. The best time to do this is right now.
Also, put together a list of nearby qualified well contractors that can quickly help you identify and fix problems associated with your well. According the University of Georgia, solutions can include:
- Replacing a leaky well cap or dug well cover
- Repairing a malfunctioning septic system
- Diverting surface water away from the well
- Renovating/deepening the well
- Drilling another well to obtain a safe supply from a deeper level of groundwater
- Removing livestock or pets from the well area21
WATER TREATMENT OPTIONS
When wells test positive for bacteria or other pathogens, there are a number of ways to treat the water.
- Shock chlorination uses very high levels of chlorine to kill bacteria. It’s a common and effective method of disinfecting wells, but requires some planning since faucets and toilets should not be used for at least 8 hours, preferably 12 to 24 hours.22 A one-time treatment may be all that’s necessary, but if a follow-up sample 10-14 days later tests positive for bacteria, the reason for contamination must be identified and corrected.
- Ultraviolet irradiation is a cost-effective, continuous treatment process that uses UV light to inactivate bacteria and viruses in your drinking water by disrupting their DNA.23 UV irradiation does not remove chemicals from your water, and water quality factors such as turbidity and suspended solids can reduce the treatments effectiveness.
- Reverse osmosis systems pass water through a semipermeable membrane to remove bacteria, viruses and protozoa.24 They also reduce certain tastes, some pesticides, high chloride content, nitrate, heavy metals, and arsenic.25 Minerals are also removed during the reverse osmosis process. Due to the equipment and plumbing costs involved, this option can be quite expensive with whole-house systems ranging from $12,000-$18,000.
- Distillation purifies water by boiling it and collecting the steam. The process removes sediment, high total dissolved solids, pesticides (if properly equipped with a gas vent), fluoride, nitrate, lead, copper and other heavy metals, arsenic, and bacteria.26 Depending on the system, and if operated properly, it may also effectively inactivate microorganisms such as bacteria, cysts and viruses.27 Distillation does not remove chlorine, chlorine byproducts, some VOCs, certain herbicides and other chemicals with boiling points lower than or near that of water.
- Gravity-fed water purification systems made by Berkey® Systems are based on a simple and efficient process that uses gravity to pull water through microporous filters or elements. This traps contaminants while allowing beneficial minerals to pass though. Berkey® systems are powerful, very cost-efficient and require no electricity or special plumbing, which makes them an ideal choice for everyday use and emergencies.
Read the following for more:
Take Control of Your Well Water With a Berkey® Water Purification System
Berkey® Systems are the top choice for everyone who is considering a gravity-fed system to purify their well water.
Berkey® System Benefits
Powerful- Berkey® purifiers remove a broad universe of contaminants, from toxic chemicals and minerals to pathogenic bacteria and virus, while leaving in the healthy minerals your body needs.
Efficient- Berkey® purifiers are the fastest-producing gravity fed water purification systems on the market, purifying water up to eight times faster that other available systems.
Convenient- The purification elements may be cleaned, eliminating frequent replacements.
Effortless- The design replaces slow and exhausting manual pumps with the natural force of gravity. At the same time the system remains simple to use, making it a breeze; whether in the kitchen or deep in the Rocky Mountains.
Portable- Berkey® purifiers travel easily and function without electricity or water pressure.
Durable- Constructed of highly-polished surgical grade AISI 304 stainless steel, the housing is built to last.
Economical- Two Black Berkey® Purification Elements, which come standard with most systems, average 2 cents per gallon of purified water, and last up to 6,000 gallons, or approximately 5-8 years with typical use.
Proven- Used by individuals, missionaries, and relief organizations worldwide, Berkey® systems have truly stood the test of time.
THE BOTTOM LINE
Berkey® Water Purification Systems address a broad universe of potential contaminants, including viruses, bacteria, pesticides, pharmaceuticals, heavy metals and even radiologicals while leaving in the healthy minerals your body needs. Confidently use your Berkey® System as a final barrier solution daily.
(1) CDC: Private Ground Water Wells
(2) Wikipedia: Water Well
(3) USGS.gov: Groundwater: Wells
(4) Government of Canada: Groundwater Contamination
(5) CDC.gov: Well Siting & Potential Contaminants
(6) EPA.gov: Potential Well Water Contaminants and Their Impacts
(7) USGS.gov: Contaminants Found in Groundwater
(8) EPA.gov: Potential Well Water Contaminants and Their Impacts
(9) USGS.gov: Contaminants Found in Groundwater
(10) CDC.gov: Private Wells
(11) EPA.gov: Questions and Answers on Fluoride
(12) EPA.gov: Questions and Answers on Fluoride
(13) CDC: Health Concerns Related to Nitrate and Nitrite in Private Well Water
(14) HealthlinkBC.ca: Nitrates in Well Water
(15) CDC.gov: Overview of Water-related Diseases and Contaminants in Private Wells
(16) EPA.gov: Private Drinking Water Wells
(17) CDC.gov: Drinking Water FAQ
(18) CDC.gov: Drinking Water FAQ
(19) Canada.ca: What's In Your Well? - A Guide To Well Water Treatment And Maintenance
(20) EPA.gov: Emergency Disinfection of Drinking Water
(21) Coliform Bacteria in Your Water
(22) NMSU.edu: Disinfecting a Domestic Well with Shock Chlorination
(23) EPA,gov: Ultraviolet Irradiation
(24) Puretec- What is Reverse Osmosis?
(25) A Guide to Drinking Water Treatment Technologies for Household Use
(26) Drinking Water Treatment: An Overview
(27) Contaminants Removed from Water by Distillation
(28) Drinking Water Treatment: An Overview
Share this Important Information
Understanding is key. Share this with others so they may make informed choices about their water.