Contaminants

BACTERIOLOGICAL

Bacteriological contamination of drinking water can result from many sources including:

· Septic system leaching
· Sewage
· Manure leaching and runoff
· Stormwater runoff
· Incomplete or ineffective wastewater treatment

Monitoring Requirements

Monitoring may be required monthly or quarterly, depending upon the system size and type, and population served.

Sampling Procedures

Sampling Preparations

Sampling site(s) must be WDNR approved. Use metal faucets if possible. Avoid sampling in rest rooms or any other sites with higher than normal possibilities of contamination. If the sample is to be mailed, determine when the mail leaves the post office and collect the sample just prior to mailing it. Plan to mail the sample early in the week and guarantee next day delivery. Avoid weekends and holidays. Plan sampling early in the sample period to make sure enough time is allowed for errors or lost samples. Ensure that the results and reports are submitted to WDNR before the end of period deadline.

Inspect the sampling bottle without opening it. If the bottle is damaged, or the cap is not fastened securely, discard the bottle and choose another one. Make sure the bottle has been provided by a laboratory and is specifically prepared for bacteriological sampling. If your system adds chlorine for disinfection, make sure the bottle contains a neutralizing agent such as sodium thiosulfate.

Sampling Procedures

As you will see in the following instructions, the basic instructions for preparing to take a bacteriological sample are known as the three "F"s; Flush, Flame, and Flush. Flushing out the line yields a representative sample of the distribution system.

1. Remove any attachments that may be connected to the faucet. Unscrew and remove the aerator/screen assembly and gasket. Turn on the water, using only the cold water. Allow the water to run approximately five to six minutes.

2. Turn off the water and sterilize the tap or faucet using a propane or butane torch. Hold the flame beneath the opening for 20 seconds, moving the flame continuously to prevent damage to the faucet.

3. Turn on the cold water and allow it to run at a slow to medium stream for five minutes. DO NOT change the flow rate or wash or wipe the faucet before sampling.

4. Remove the cap from the bottle without touching the inside of the cap or bottle. Hold onto the cap and bottle with your fingers away from the edge and away from splashing water. DO NOT set the cap down. DO NOT rinse out the bottle.

5. Without allowing the bottle to touch the faucet, hold the bottle under the flow until water is ½ inch from the top. Immediately replace the cap securely. If supplied with a plastic bag, place the bottle in the bag and close the bag. Turn the water off. Replace any attachments removed prior to sampling.

Reporting and Delivery

Once a sample has been collected, complete a WDNR-approved sample information form (click here for sample form in PDF format). Place the sample and completed form in the supplied package, and deliver to the post office or lab.

Bacteriological samples must be analyzed within 48 hours of collection. Check with your post office for the best and fastest way to deliver, or use a different carrier to meet this requirement.

Follow-up Sampling

Follow-up sampling is required for any total coliform positive sample. Collect samples from sites listed in the WDNR approved sampling site plan. If a follow-up sample is total coliform positive, the positive sample is tested either for fecal coliform or E. Coli. The test should be done automatically by the lab and does not require an additional sample.

Take four follow-up samples within 24 hours:

Same location (check sample)
One upstream
One downstream
One other location

Take five samples in the next service month from any location listed in the WDNR approved sampling site plan. If none of these five samples test positive for total coliforms, you may resume collecting your usual number of routine sample the next month..

Reporting Requirements

If you have a total coliform positive sample followed by a fecal coliform or E. Coli positive sample, this is a serious potential health risk. This creates an acute MCL violation and you must:

· Notify the WDNR by the end of the day, or before the end of the next business day if the WDNR office is closed.
· Notify the public within 24 hours by television, radio, hand delivery, or other method approved by the WDNR.
· Advise your customers to boil their water.

The WDNR shall only accept analytical data from certified labs that report directly to the WDNR.

Treatment Options

If a bacteriological problem is associated with the source water for the system, installation of a new well into an uncontaminated aquifer may be necessary. If a new well is not an option, water treatment to remove or inactivate pathogens (disease-causing microbes) may be necessary. Common water disinfection techniques include:

Health Effects

The presence of disease causing bacteria in drinking water can cause symptoms such as nausea, cramps, diarrhea or headaches. For most people, these effects are short-term, as their bodies can fight off microbes in much the same way they fight off germs. However, they can be dangerous to infants, the elderly, and those people whose immune systems are already weakened.