To make sure it is safe for drinking. Even if your water tastes and smells normal there can be bacteria and chemicals present. If you notice a change in your water quality it is also advised to test your drinking water. If treatment is necessary, it is also important to have your water tested so you can put in the correct system.
If the odor is from the hot water faucet only it is likely a problem in the water heater. If the odor is coming from both the hot- and cold-water faucets, but not from faucets not connected to a water softener the problem could be sulfur bacteria in the water softener. If the odor is coming from both the hot- and cold-water faucets but the smell becomes less noticeable after a few minutes it is likely sulfur bacteria in the well or plumbing system. If the odor is coming from both the hot- and cold-water faucets but the smell stays the same no matter how long you run the water the problem is likely hydrogen sulfide gas. Bacteria and manganese can also cause undesirable odors in drinking water.
Lead is not a naturally occurring groundwater contaminant in Maine. If lead is present it usually comes from plumbing installed before or during the 1970s. Pipes, faucets, fixtures, water mains, service lines, soldering, and goose necks can all contain lead. Even if your home is supplied with water from a public water system it is a good idea to check your drinking water for lead with a first draw lead test. This test allows you to see how high the lead concentration is when the water sits in your plumbing. It is recommended to be tested every 5 years.
Most drilled wells are drilled through rock, sand, or gravel which can contain arsenic. Arsenic is part of the earth’s crust. Arsenic is a groundwater contaminant issue in Maine.
Maximum contaminant levels (MCL) the highest level of a contaminant that is allowed in drinking water. MCLs are set as close to where the level of a contaminant in drinking water below which there is no known or expected risk to health. MCLs are enforceable standards. Secondary maximum contaminant levels are levels set for contaminants that may cause cosmetic and aesthetic (skin/tooth discoloration, taste, odor, and/or color) effects in drinking water. The following link is to EPA’s table of MCL’s and secondary MCL’s: https://www.epa.gov/sites/production/files/2016-06/documents/npwdr_complete_table.pdf
A bacteria test should be performed annually to check for total coliform bacteria and E. coli bacteria. Every three to five years arsenic should be tested. If your home was built in the 1970s or before lead should be tested every three to five years. If you are having issues with your water quality (staining, odor, taste, color) are looking to install a water treatment system a Standard Test is recommended. This tests for total coliform bacteria, E. coli bacteria, nitrate, nitrite, chloride, pH, hardness, copper, iron, and manganese.
For total coliform and E. coli bacteria sampling you want to remove any attachments on the faucet, disinfect the faucet with alcohol, allow the cold water to flow for 10-15 minutes before sampling, do not rinse or overfill the container, and do not touch inside the sample bottle or cap. You want to avoid outdoor faucets; faucets connected to cisterns, softeners, pumps, pressure tanks or hot water heaters; new plumbing/fixtures or ones that were recently repaired; threaded taps and swing spouts; and leaky faucets. Sampling instructions are included in every test kit. Washing your hands is an easy way to protect your sample from a sampling error.
If there is still chlorine in your water supply when you go to test your drinking water bacteria may not be detected because chlorine is still present. To get a more accurate result it is recommended to wait one to two weeks after flushing chlorine from your well before testing it for total coliform and E. coli bacteria. If you have a chlorinator, please request a test with preservative to neutralize the chlorine. If you have recently disinfected your water supply you can request a residual chlorine test kit. This kit is prepared so you may run the test at home to make sure the chlorine has been flushed out properly before collecting a sample. Using bleach/chlorine to disinfect a faucet before sampling can also lead to a sample being rejected due to chlorine content.
If so, you are most likely only due to check for total coliform and E. coli bacteria.
If not, you are most likely due to check for total coliform bacteria, E. coli bacteria, nitrate, nitrite, and arsenic.
If your home was built in the 1970s or before you may be due to check for lead as well.
If so, you should check for total coliform bacteria, E. coli bacteria, nitrate, nitrite, arsenic, pH, chloride, copper, iron, manganese, and hardness.
If not, see here: ‘What Do I Test For?’