Submitting Water Samples for Analysis
- A correctly taken water sample will help ensure accurate results.
- Bottles should be rinsed with water prior to taking the sample. If soap is used to clean containers, the bottle should be rinsed thoroughly prior to sampling - detergent can contain some phosphorous and other minerals that may contaminate the water sample.
- Labels on the sample should include name, address, phone number, and location. An information sheet with the name, address, and type of test desired should accompany the sample. Samples should be sent to the laboratory as soon as possible, since some tests have to be done immediately (such as pH) or within 24 hours (such as alkalinity) to be accurate.
- Obtaining a representative water sample is a first step towards determining water quality. Water samples should be placed in plastic containers that can be sealed tightly with plastic caps. Sample containers should be at least four fluid ounces. A four-ounce sample is enough to do major cations (Ca, Mg, Na, K), major anions (CO3, HO3, CI, SO4, NO3), pH and electrical conductivity. If additional testing were required, more samples would be necessary.
- The container and lid should be rinsed three times with the water being sampled. With the water flowing, the container should be filled to the top with as little air as possible in the container. Seal the container, label it with a waterproof marker, and place the sample in the refrigerator. To sample water at the point of consumption, it is desirable to obtain the sample first thing in the morning, prior to using any water elsewhere in the house. The sample should be taken from a cold-water faucet furthest away from where the water enters the house. Do not allow any water to flow prior to taking the sample. Obtain the sample in a clean container, completely filling the container with sample water. Water that has stood in pipes all night will generally have the potential to contain higher levels of heavy metals such as lead, especially if lead solder or lead pipes were used in the household plumbing. Place the sample in the refrigerator until it can be taken or sent to a laboratory. Do not freeze water samples.
- To sample the primary water source, allow water to flow about five minutes from a faucet on the main line, if available, or as near the water source as possible. The five-minute purging process will help remove any sediment that may have settled into the well casing or pipes and allow the sampling of fresh ground or surface water.
- When obtaining samples, there are generally two points at which samples may be taken. The first point is at the primary source such as a well head, spring, or lake prior to entering the household plumbing system or undergoing any on-site treatment. The second point is at the site of consumption such as the kitchen water faucet where the water has passed through the household plumbing. Samples from the secondary site within the household may be influenced by the effect the plumbing has on water quality.