Labs often will only accept samples taken in their collection bottles. Also complete all the forms the lab requires to process the sample. A water sample needs to be submitted to the lab within 48 hours of collection. In some cases it must be kept cold prior to testing. Care must be taken to prevent anything but the water from contacting the inside of the bottle or the cap.
Contaminants are often present in small amounts.
Careless sampling prevents accurate test results. Do not take the sample from a swing-type faucet. Inspect the faucet for leaks. Select another faucet if there is leaking. Remove the aerator.