Residential Water Sampling Instructions

Please read through all directions before proceeding. Plan out your actions to ensure proper sampling.

1. Determine the point at which you will sample. If you have any type of water filter, softener, or treatment system, you need to decide if you want to get a raw or treated sample (or both). Typically, a raw sample is taken at the well tank or an outside spigot. A treated sample is commonly taken from the kitchen faucet or bathroom sink. Do not sample if you have recently chlorinated your system until the system has been “pumped-off.” The system must be run until all traces of chlorine are gone. Chlorine will adversely affect testing, give inaccurate results, and can even damage sensitive lab equipment.

2. Prepare the sampling spigot. If present, remove any aerator or screen from the end of the spigot. If you are unable to do so, you may still take the sample, but note this on the chain of custody (see #6). If you are sampling for bacteria (e.g., coliform), sterilize the spigot. To sterilize a metal spigot, flame with a match or lighter for 5 to 10 seconds. Note that some spigots are actually plastic coated to look like metal. To sterilize other types of spigots, wipe down with a dilute bleach solution and a clean paper towel.

3. If you need to do a “first draw” sample (a special type of lead and copper test), you must draw your sample after the water has been unused for six hours. Plan sampling time accordingly (e.g., first thing in the morning). If this is the case, draw this sample first before running the water. It is usually taken in a tall, round, 1 L (~1 qt) opaque plastic bottle.

4. Once the first draw is completed, or if it does not apply to you, allow the cold water to run on full for 5-10 minutes. Double the flush time if you were unable to remove the aerator or screen in step #2. Then slow the flow to a pencil-thin stream.

5. Begin sampling- open each bottle only when you are about to fill it. Start with bacteria sampling first. This is a clear, round, 100 mL (~4 oz) bottle with a small pill in the bottom. Do not discard the pill and do not touch the interior of the bottle or cap. Fill the bottle to just above the “fill line” indicated on the bottle and firmly snap the lid closed and secure with the locking tab. Next fill your chemistry bottle. This will be an opaque plastic bottle, usually a round, tall, 500 mL (~16 oz) bottle with a small cap. You may be furnished with (a) different bottle(s), depending on your testing needs. Fill to the shoulder of the bottle(s) and then cap the bottle(s).

6. If applicable, sample for Volatile Organic Compounds (VOC) and/or radon last. These are sampled in 40 mL (~1.5 oz) glass vials with a plastic cap. The center of the plastic cap has a hole in the top, exposing a rubbery seal (this is normal). Slow the flow to half of a pencil-thin stream, and fill each vial until the water forms a crown at the lip (without overflowing). Immediately cap tightly. Invert the vials to check for air bubbles. If a bubble any larger than a pea is present, uncap, top-off, and re-cap the vial. If you were furnished with (an) additional VOC vial(s) that were already filled, do not open them. These are called trip blanks and are for lab quality assurance purposes.

NOTE: VOC vials are preserved with a few drops of hydrochloric acid, a strong acid (HCl). USE CAUTION. Should you come in contact with the acid, flush affected area under running water for a few minutes. Do not rinse the acid out of the vials before filling them- this acid is needed to preserve the sample.

7. Fill out a Chain of Custody. If you do not have one, you may download one here. Include your name, address, phone, e-mail (if applicable); the sampling address, location (such as kitchen faucet), date, and time. Also record any unusual circumstances, useful information (such as whether the sample is before or after any filtration system or softener), or problem you had taking the sample

8. Return the samples to the lab as quickly as possible. If you can not return to the lab immediately after taking samples, they should be refrigerated or stored in a cooler with cold/ice packs. Samples must be returned within 24 hours of sampling. We ask that you plan on getting your samples to us before 4:30 p.m. to allow essential testing to begin before the close of business.