This portion of the database reports certified test results for a set of gas well "signature chemicals" that are designed as a screen for possible contamination of groundwater from waste produced by high volume horizontal hydraulic fracturing operations (fracking) in New York's Marcellus and Utica Shale regions. Over half the results were paid for by individual homeowners who contracted with CSI for pre-fracking baseline tests of their private drinking water wells. The balance of the results were produced by CSI under two contracts, one with the Institute for Health and the Environment (IHE) at SUNY-Albany and the other with the Otsego County Conservation Association (OCCA). We thank our private clients, SUNY-Albany and OCCA for permission to pool their test results for anonymous presentation on our website.

In order to protect homeowners' privacy, drinking water wells are mapped to 1-mile grid squares and not to specific addresses. Groundwater data are presented at three geographic levels. This page shows a map and graphs of results for the region comprising the counties where groundwater wells have been tested. Results for counties within this region may be accessed from the list at the lower left. Grid squares measuring one square mile may be accessed from county pages. Data for individual wells (but not individual well locations) are accessed from grid square pages.

Grid squares are identified on maps by centroid markers placed in the middle of 1-mile grid squares where groundwater wells have been tested. Any overlap that may occur between a centroid marker and the address of a private residence is purely by chance.

• Samples were collected from private drinking water wells by CSI staff, preserved and transported to the CSI lab on ice the same day for processing with chain of custody documentation.
• Virtually all of the samples collected represent untreated well water. If treatment systems were present, CSI made every effort to bypass these systems, often by sampling from the client's pressure tank.
• Samples were assumed to be representative of groundwater if the residence was occupied.
• Additional flushing was performed on rare occasions when a residence had not been occupied for a period of time.
• Analyses were performed by CSI and three subcontract labs using certified methods and quality assurance/quality control criteria approved by the New York State Department of Health - Environmental Laboratory Approval Program.
• Quality assurance and quality control documentation is available on request.