Does your drinking water come from a private well? Do you know what's in it? Is it safe for you and your family to drink?
When was the last time you had your private well water tested? Five years ago? Ten years ago? Never?
These are all questions that were asked in a St. Charles County Department of Community Health and the Environment newsletter published in June 2001. Since that time, many new residents have purchased property in St. Charles County with existing private wells. Most of the material in this edition of "From The Director" is from our previous newsletter. It has been updated and links to good Internet resources have been added.
The number of private drinking water wells in St. Charles County is estimated to be in excess of 5,000. Many of those wells are more than 20 years old and were built before any minimum construction standards were established by the Missouri Department of Natural Resources. Whether old or new, the bacteriological and chemical quality of the water produced by private wells is not required to be routinely tested by anyone. Therefore, it’s up to you as the owner of the well to ensure that the water that you consume is safe to drink.
What to Test For
- Bacteria
The most common test used to check the quality of all drinking water is the sample for coliform bacteria. This broad category of bacteria is associated with fecal waste of humans and animals. Its presence in well water indicates that contaminated surface water or septic tank effluent may be getting into a well. The design of a well is intended to keep surface water out but various types of water-tight seals used on wells can dry out, crack, and leak over time. - Nitrate
The presence of high nitrate levels in well water is generally an indication of surface water contamination entering the well. Nitrate levels above 10 parts per million (expressed as nitrogen) are of particular concern if infants will be consuming the water. The digestive system of infants converts nitrate into nitrite which interferes with the blood’s ability to carry normal amounts of oxygen, a condition known as methemoglobinemia. - Fluoride
Naturally occurring fluoride may or may not be present in your well water depending on the composition of the bedrock through which the water flows. Fluoride plays an important role in the reduction of tooth decay and the optimum amount in drinking water is 1 part per million (PPM). Excessive amounts have been shown to cause a brown mottling discoloration of the teeth known as dental fluorosis. Most well water in St. Charles County is very low in fluoride, but some localized areas have levels exceeding 3 PPM. Some pediatricians request parents of their young patients to have private well water tested for fluoride. - Other chemicals A variety of chemical tests are available to help determine the cause of specific problems associated with individual well water supplies.
For Example:
- Calcium, magnesium, alkalinity, and hardness are all associated with hard water which tends to clog pipes and water heaters with mineral deposits.
- Iron and manganese, which give water a metallic taste and can cause red, brown, or black stains on fixtures (sinks, tubs, toilets) and laundry.
- Sodium may be a concern for anyone on a medically restricted low-salt diet, especially if a water softener has been installed on the system. Water softeners add sodium to the water in proportion to the amount of hardness they remove.
How Often to Test
The Missouri Department of Health recommends that all private well water supplies be tested for coliform bacteria at least once a year. New wells should also be tested for a standard series of common chemicals in order to establish a baseline of drinking water quality. Routine testing for specific chemicals may be appropriate on an individual basis. Remember that a well is a man-made hole in the ground that interacts with Mother Nature. Conditions can change over time that affects the safety of the water you drink from any source. But, the quality of private well water is tested only when you have it tested.
What Does It Cost
The Missouri Department of Health Laboratory provides appropriate bacteriological for private drinking water supplies. They supply the Department of Community Health and the Environment with approved sampling containers which we provide at no charge to you. After the water sample is analyzed by the state laboratory, they will bill you a standard fee per sample. Currently that standard fee is $10.00 per sample. Please note, the State Public Health Laboratory no longer provides chemical testing. The Division of Public Health, Environmental Public Health Section, maintains a list of private testing laboratories that do provide that service for a fee. You can get that list by calling (636) 949-7400 Ext. 4204.
What if I'm on a Public Water Supply?
If your drinking water comes from a public water supply (a system that serves 20 or more people) such as: city, municipal, county water district, subdivision community well, mobile home park community well, etc., then it is already tested routinely by the Missouri Department of Natural Resources (MDNR). This is a mandatory testing program when the water supply is a public supply. The results of those tests are available by contacting MDNR via the Internet at www.dnr.mo.gov.
To Sum Up
Information on private well testing and public water testing can be found on the Department of Community Health and the Environment website. Once again, if you have questions or concerns about your private drinking water supply, contact us − we can help.
St. Charles County Department of Community Health and the Environment
Division of Public Health
1650 Boone's Lick Road
St. Charles, Missouri 63301
Telephone (636) 949-7400 Ext. 4204
Fax (636) 949-7403
Website www.scchealth.org
Interesting Links:
Centers for Disease Control − Water Wells
EPA Private Well Page
Missouri Department of Natural Resources Public Drinking Water Page