Chain of Custody Water Testing
A "chain of custody" or "third-party" water testing is conducted to legally document water quality before a nearby activity or land use change, such as gas drilling, mining, or construction, etc., but may also be used in some real estate transactions. Samples for this type of testing should be collected by professionals and delivered to a state-accredited water laboratory. All individuals who handle the sample are documented on the chain-of-custody form to show that only unbiased professionals have had access to the sample. This also ensures that the sample is collected using proper protocols and analyzed using proper analytical methods. It is up to each laboratory to then determine which lab employees or independent consultants are qualified to collect and submit samples to their laboratory. Using this chain-of-custody process ensures that the water quality results will be more useful in any potential legal proceedings related to contamination of drinking water supplies by nearby activities.
The entire list of water testing laboratories accredited by the Pennsylvania Department of Environmental Protection (DEP) can be found on their website. Once on that site, scroll down to the Laboratory Accreditation Program Resources, where you will find the links for the "Search Environmental Laboratories". This link leads to a tool with a search function that allows you to find accredited laboratories across the state based on location, type of sample to be tested, substance to be tested in the sample, and testing method. A detailed instruction sheet on how to search laboratories on this tool is available on the PA DEP website: Instructions for use of "Search PA Accredited Environmental Laboratories". Here is a summary:
- Select drinking water in the "Matrix" tab
- Choose the substance to be tested for (e.g., bacteria, arsenic, atrazine, etc.) in the "Analyte" tab.
- The "Method" tab can be used to select a desired testing method. If you do not know the testing method you want to use, you can select all.
- Choose commercial only under "Lab Type"
- A specific county can be selected in the "PA County" tab, or you can select all to see a list of labs across the state.
- Click "View Report" on the right-hand side of the page.
 Not all state-accredited laboratories offer chain of custody services. Therefore, clients seeking chain-of-custody testing should confirm with each laboratory that they can, in fact, provide this service. Some labs are accredited for many water testing parameters, while others may only be accredited for a few (like bacteria). When discussing chain-of-custody water testing with a state-accredited laboratory, confirm that they hold current state accreditation for all of the water test parameters or substances that you are interested in testing in your water supply.
The state-accredited Agricultural Analytical Services Laboratory at Penn State does not provide chain-of-custody water testing service.
To document the yield of a well before a land use change, a homeowner can contract a well driller or other professional rather than a water quality testing laboratory. Yield testing results will vary depending on the technique used and natural hydrologic changes.
