Contrary to popular belief, groundwater doesn’t exist in huge underground caverns in the form of underground lakes. Groundwater actually exists in the pore spaces between soil or rock particles. When all the pore spaces are filled up and the soils and rocks are saturated, an aquifer is formed. Sometimes groundwater can feed into lakes, streams, or other surface waters or it can be drawn out of the ground and used for drinking water by wells.

Over 50% of people use groundwater as a source of drinking water, therefore groundwater quality is important. While surface waters are easily polluted, groundwater is somewhat protected by the soil that not only covers it, but also acts as a filter when groundwater passes through it. However, soil cannot filter out many of the pollutants humans generate, and groundwater is at greater risk of becoming contaminated.

Groundwater contamination occurs when any man-made products such as gasoline, oil, road salts, and chemicals get into the groundwater and cause it to become unsafe and unfit for human use. Some of the major sources of these products are storage tanks, septic systems, hazardous waste sites, landfills, and the widespread use of road salts and chemicals. An important fact to remember is that water is part of a cycle, and that any chemical released into the air also has the potential to get into the groundwater.

Groundwater can also easily become contaminated if a well is constructed improperly or if toxic materials are released near the well, especially if the well has been abandoned but not properly plugged. Toxic chemicals spilled or dumped near a well can leach into the aquifer and contaminate the groundwater drawn from that well. Contaminated groundwater can be especially dangerous if used for drinking water. Wells can be tested to see what chemical may be in the well and if they are present in dangerous quantities.

Water naturally evaporates from the surface waters of the earth and transpirates out from plants. Eventually, it accumulates in the atmosphere and forms clouds. When conditions (temperature and weather) are suitable the vapor condenses and falls back to the earth as precipitation (rain, snow, hail, etc). Precipitation then either runs off the earth’s surface to open waters (lakes, rivers, and streams) or penetrates the earth’s surfaces and percolates down to underground aquifers and becomes groundwater.

According to the United States Geological Survey (USGS) figures, groundwater provides an estimated:

A well is a hole drilled into an aquifer to draw or monitor water. 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. Well permits are available at the Environmental Health Office for new construction or replacement systems.

There are some easy steps to acquiring a well for your property:

Once the permit is issued, a well driller may then be contacted and the well can be drilled.

Well Driller and Homeowner Responsibilities

After the well is drilled, the well contractor and the homeowner have some responsibilities. The well driller is required to chlorinate (sanitize) the well. The contractor must fill out and submit a water well record (well log) to the homeowner, the local health department, and maintain a copy for his/her records. The well log must be submitted to the health department within 60 days of well completion for our review for timeliness, accuracy, and completeness.

The health department requires sampling of all new wells for the presence or absence of coliform bacteria. It is the homeowner’s responsibility to acquire this sample. Sampling is to occur prior to placing the well into service and after all traces of chlorine have been flushed from the well and distribution system. Collection bottles are available at the health department.

Final Inspections

Upon completion of the well, pump, and pressure tank installation, the homeowner should contact the health department to schedule a final inspection of the exterior and interior portions of the well. An exterior inspection consists of checking the well construction (proper construction materials, pitless adapter, screened well cap, etc.), casing termination, isolation distances, etc. An interior inspection consists of checking the pressure tank, pump (if applicable), pressure line, valving, and sample tap.

During the final inspection, a sample of the water supply may be collected for coliform bacteria. (The lab fee for a bacteria test is currently $12, and is the homeowner’s expense). The homeowner can also request a partial chemical analysis (fee of $14) of the water to be conducted. The partial chemical test consists of checking the levels of fluoride, chloride, hardness, nitrate, nitrite, sulfate, sodium, and iron in the water. The homeowner can either come into the health department and pick up the sample bottles themselves and mail or drive them to the state lab or have a health department sanitarian conduct the sample collection. Once the samples have been gathered, they are sent to the state lab for analysis. The results usually come back within two weeks and are sent to the homeowner as well as the health department.

It is not uncommon for wells to quit functioning or fail to produce water after a certain period of time, and a replacement well needs to be constructed. If this happens the old well needs to be properly abandoned (plugged). An old well can allow runoff water to flow directly down to the aquifer, and carry contaminants into the groundwater. This allows the runoff water to bypass the natural filtration process caused by percolation of water through the soil. Plugging of an abandoned well must be done in accordance with the law and only performed by a licensed well driller. After the well is plugged an abandoned well record is sent to the health department for review.

Testing Your Water

There are two main things to look for when testing water: the presence or absence of coliform bacteria, and the level of nitrate in the water. Coliform bacteria are commonly found in soils, on vegetation, and in surface water, as well as in the intestines of mammals. Bacteria washed into the ground by rainfall or snowmelt are usually filtered out as water seeps through the soil. Properly constructed water wells do not typically harbor coliform bacteria and coliform bacteria do not occur naturally in Michigan aquifers. However, they can be introduced into a well during construction and can remain if the water system is not thoroughly disinfected.

Testing for coliform bacteria is required for all new well construction. However, a bacteria test is recommended for a system if:

Nitrates are naturally occurring compound composed of nitrogen and oxygen, and is one potential contaminant of groundwater. Human activities are often responsible for creating elevated levels of nitrate in the ground. The overuse of chemical fertilizers and the improper disposal of human and animal wastes can cause contamination. Once in the soil, nitrate is extremely soluble in water and can move easily through the soil in the drinking water supply.

Call or visit the health department to inquire about proper sampling bottles and sampling procedure.

For new wells the sample must be collected from the pressure tank sample tap.

For routine monitoring and existing wells, a clean, well-maintained, and frequently used faucet should be used to collect the sample.

Flush out your water system for at least 15 minutes before collecting your sample. Then, carefully remove the plastic wrapping from the top of the bottle, and remove the lid, taking great care not to touch the underside of the lid, as well as the inside of the bottle. Humans do carry bacteria on our hands (as much as we don’t like to think we do), and touching the inside of the sample bottle could contaminate the sample. Allow your water to run at a steady rate, but not at a high pressure. Fill the bottle to the fill line on the bottle. Then place the lid securely on the bottle, place it back into it’s packaging with the fee, refrigerate it, and return it to the state lab within 30 hours of taking the sample. It is recommended that the sample be collected near to the time that the post office takes out the mail. Samples that are received at the lab over 30 hours old will need to be repeated.

First of all don’t panic.

Either resample immediately at the original location or chlorinate your well and repeat the sample. Discontinue drinking or brushing teeth with water until you have a safe sample result. Either use bottled water for consumption or bring the water to a rolling boil for at least three minutes before consuming to kill the bacteria.

For new wells, which have been sampled at the pressure tank sample tap, contact your well driller to disinfect your well. After thorough flushing, have the system sampled again at the same faucet.

If you are unable to obtain a satisfactory ("negative") result, contact the Environmental Health office for consultation.

The U.S. Environmental Protection Agency has established a maximum contaminant level for nitrate (as nitrogen) at 10 milligrams per liter (mg/L) or 10 parts per million (ppm). Private water supply owners with excessive nitrate should contact the Environmental Health offices for assistance.

Nitrate in drinking water is not likely to cause health risks for healthy adults. The ingestion of high amounts of nitrate can cause adverse health effects in infants or susceptible adults, however. High levels of nitrate are known to cause methemoglobinemia. Normal hemoglobin carries oxygen through the bloodstream, but when hemoglobin is converted to methemoglobin, less oxygen can be transported. As a result, vital tissues including the brain receive less oxygen than they need. The most severe cases can result in brain damage or even death. Fortunately, methemoglobinemia is uncommon, easily recognized by physicians and can be readily diagnosed and treated.

If a well is generating nitrates above 10 mg/L, it is recommended that an alternate source of drinking water be developed, where possible, and bottled water be used for preparing infant formula. The Environmental Health offices should be consulted for information on deepening or re-drilling the well to reduce nitrate levels.

Although there are treatment devices, which can remove nitrate from drinking water, this equipment requires frequent, careful maintenance and sampling to operate effectively. Improperly installed, operated or maintained equipment can result in nitrate passing through the treatment process. In some cases nitrate will be concentrated above the incoming levels. Bacteriological problems can also develop in improperly installed and poorly maintained treatment systems. If a satisfactory level of nitrates cannot be obtained from a new well and the use of a nitrate removal system is to be used, one with National Sanitation Foundation or equivalent certification should be selected. Boiling water will not remove nitrate and can concentrate it.

If nitrate contamination is known to the area, or a sample indicates nitrate levels approaching 10 mg/L, a minimum of annual sampling is recommended.

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