How to Collect a Well Water Sample (Step by Step)
Short answer: use the bottles the lab gives you, sample from a cold tap before any filter or softener, don't touch the inside of the bottle or cap, keep it cold, and get it to the lab within the time they give you.
Steps
- Get bottles from a certified lab. Different tests need different bottles, and some contain a preservative. Don't rinse them out.
- Pick the tap. Use a cold kitchen tap or an outside tap before any treatment, unless the lab asks for treated water. Avoid swivel or leaking faucets.
- Remove the aerator (the screen on the tip) for bacteria samples. Labs often ask you to disinfect the tap tip.
- Run the water for as long as the lab says, often several minutes, so you sample fresh well water. For a lead test, the lab may want the first water out instead.
- Fill to the line. Don't let the cap touch anything. VOC vials must have no air bubbles.
- Label and fill in the form with date and time.
- Keep it cold and deliver or ship it fast. Bacteria samples have the shortest time limit, so sample early in the week, never right before a weekend or holiday.
Common mistakes
- Sampling after a water softener or filter.
- Sampling right after shock chlorination (wait as the lab advises).
- Mailing a bacteria sample on Friday.
Not sure which bottles you need? Use Which test do I need?
Sources
- EPA: Private drinking water wells
- CDC: Testing water from private wells
- EPA: Protect your home's water
Questions
Can I use my own bottle?
No. Use the lab's bottles. Many are sterile or contain a preservative needed for the test.
Which tap should I use?
A cold tap before any filter or softener, unless the lab tells you otherwise.
How fast must the sample reach the lab?
Follow the lab's time limit. Bacteria samples have the shortest window, so sample early in the week.
Free well water checklist
15 family-friendly steps based on CDC and EPA guidance. Print it, keep it on the fridge, and know when to call a certified lab.
More guides
- FHA, VA and USDA Loan Well Water Test RequirementsLoan rules for well water tests, side by side, from HUD, VA and USDA handbooks.
- Mail-In vs Drop-Off Well Water Testing: Which to ChooseThe 30-hour bacteria clock, and which tests travel well by mail.
- How Much Does Well Water Testing Cost? Real Lab PricesReal published prices from public labs, free programs, and the EPA-approved-lab myth.
- Testing Tap, Spring, Lake, River or Pond WaterTap, spring, lake, river and pond water: where to test, and why pools and aquariums are different.