Private Well Water in New Jersey
Private wells are not regulated the way public systems are. If you own a well, you are responsible for testing, maintaining, and treating your own water.
Short answer: Test your well routinely on your own schedule using an NJ-certified laboratory. If you are buying, selling, or renting the property, separate, mandatory Private Well Testing Act sampling generally applies — see our Real Estate Water Testing guides.
Who this is for: homeowners on a private well, buyers considering a well-supplied property, and anyone comparing well-water treatment options.
New Jersey context
New Jersey has geology-driven concerns that vary by region, including coliform bacteria and E. coli, nitrate, volatile organic compounds, arsenic, gross alpha activity, uranium, radium-related concerns, iron and manganese, pH, PFAS, and in some coastal areas, sodium or chloride from saltwater intrusion. No contaminant should be assumed present at a specific property without a test — geology and neighborhood patterns are not a substitute for sampling your own well.
Guides in this section
Routine Well Testing
How often to test, what to test for, and how to build a testing calendar.
Read the guide →Find an NJ-Certified Lab
How to find and evaluate a certified drinking-water laboratory.
Read the guide →Understanding Well Test Results
How to read a lab report, comparison values, and what results do and do not tell you.
Read the guide →Common mistakes
- Assuming a neighbor's clean test means your well is fine
- Collecting a sample yourself for a Private Well Testing Act transaction
- Buying treatment equipment before testing for the specific contaminant it's meant to address
- Skipping retesting after installing treatment
When professional help is appropriate
After you have a test result in hand, a qualified well or water-treatment provider can help match treatment to the specific issue identified. Before that, a well contractor can help with permits, well records, or decommissioning an unused well.
Official sources
- NJDEP Private Wells and Private Well Testing Act program
- NJDEP Division of Water Supply & Geoscience
- U.S. EPA private well guidance
Related
- NJ Private Well Testing Act overview
- Public Water guides (if you are on a public system)
How often should I test my private well?
There is no single statewide mandate for routine (non-transaction) private-well testing frequency. Common practice is annual bacteria testing with periodic broader testing; see our Routine Well Testing guide and confirm current recommendations with NJDEP or your local health department.
Is routine testing the same as Private Well Testing Act testing?
No. Routine testing is optional and homeowner-directed. PWTA testing is generally mandatory for covered real-estate sales and leases and must follow NJDEP-specified sampling and laboratory requirements. See our Real Estate Water Testing guides.
This page provides general educational information and is not medical, legal, laboratory, or regulatory advice. NJ Water Quality is an independent resource and is not affiliated with NJDEP.
Last reviewed: 2026-07-11. Report a correction.