How to take a water sample

A good submission takes about 15-20 minutes in the field. Follow these steps so your data is trustworthy enough to sail through moderator review — and useful to your neighbors.

Safety first:never drink raw sample water. Wash your hands after sampling. If you see a chemical sheen, dead fish, strong odor, or suspect an active spill, don’t test it yourself — contact your local health department or the National Response Center instead. Field test kits are for screening and public awareness, not medical or regulatory decisions — always confirm concerning results with a certified laboratory.

1. Gather your tools

Item	Why you need it
Nitrile gloves	Protects you from contact with contaminants and keeps your sample uncontaminated by your hands.
Sample bottles/containers	Use sterile bottles for bacteria testing; rinsed, clean containers for chemical tests. Never reuse a bacteria bottle for a chemical sample.
Test strips or a field kit for your target pollutant	Colorimetric strips exist for lead, copper, arsenic, nitrate, chlorine, and pH. Bacteria needs a presence/absence kit (e.g. Colilert-style). PFAS and precise metal concentrations require a certified lab — no field kit is accurate enough.
Turbidity tube or handheld meter	Gives an immediate cloudiness reading and flags whether other tests might be less reliable.
Cooler with ice packs	Needed if you're sending a bacteria or lab sample out — most biological samples must be kept cold and tested within 24-30 hours.
GPS-enabled phone	To log an accurate latitude/longitude, or at least the nearest ZIP code, for the map.
Permanent marker & labels	Label every sample with site name and date/time immediately — samples are easy to mix up in the field.
Camera	A photo of the site helps moderators verify your submission and gives other users useful context.

2. Know which pollutants matter for your site

Home tap

Test for: Lead, copper, chlorine & disinfection byproducts, pH, nitrate

Test both a 'first draw' sample (water that sat in the pipes overnight/6+ hours) and a flushed sample (after running water 2 minutes) if you're checking for lead — the difference tells you whether your plumbing is the source.

Private well

Test for: Arsenic, nitrate, bacteria (E. coli/coliform), pH

Wells aren't covered by EPA's public water system testing requirements, so you're the only line of defense — test at least once a year, and after any flooding.

Lake or pond (recreational)

Test for: E. coli/coliform bacteria, turbidity, pH

Sample away from the immediate shoreline (waterfowl droppings concentrate there) and avoid testing right after a heavy rain, when bacteria counts spike from runoff — note that in your submission instead of skipping it.

River, stream, or trail water source

Test for: E. coli/coliform, turbidity, nitrate; PFAS if near an airport, military site, or industrial discharge

Sample mid-stream if it's safe to do so — water quality right at the bank can differ from the main flow.

Campsite water source

Test for: E. coli/coliform, turbidity, nitrate

If you're evaluating drinkability for backcountry use, note that field test kits are for awareness/reporting only — always filter/treat backcountry water regardless of what a field test shows.

3. Where and how to collect the sample

Choose a spot with flowing or representative water — avoid stagnant edges, visible debris, and standing puddles unless that’s specifically what you’re assessing.
Put on gloves before opening your container.
For chemical tests: rinse the container with the sample water two to three times before filling. For bacteria tests: do not rinse a sterile bottle — open it right before dipping, fill without touching the inside of the cap, and close immediately.
Submerge the container 6-12 inches below the surface, facing upstream if there’s current, and avoid stirring up sediment.
Label the container immediately with site name and date/time.
Run tests that need to happen immediately (pH, chlorine, turbidity, temperature) within minutes of collection — these change quickly. Keep bacteria or lab-bound samples on ice and get them tested/shipped within 24-30 hours.

4. Test method by pollutant

Arsenic (As) · details

Field arsenic test kits (strip-based, ~30 min) give a screening estimate; confirm with certified lab ICP-MS testing, particularly for private wells which are not covered by EPA's regulated public water testing.

Chlorine & Disinfection Byproducts · details

DPD colorimetric test strips or a handheld chlorine meter give an immediate field reading of free/total chlorine.

Copper (Cu) · details

Field colorimetric test kits give a same-day estimate; lab ICP-MS confirms precise concentration.

E. coli / Total Coliform Bacteria · details

Field presence/absence test kits (e.g. Colilert-style) give a same-day yes/no result; quantitative MPN or membrane filtration testing at a certified lab is needed for an exact count.

Lead (Pb) · details

Field colorimetric test kits give a rough screen; for anything above trace levels, send a sample to a certified lab for ICP-MS analysis — this is the EPA-recommended method for compliance-grade results.

Mercury (Hg) · details

Field test kits are limited and mostly qualitative; certified lab analysis (cold vapor atomic absorption spectroscopy) is recommended for a reliable reading.

Nitrate (as N) · details

Field test strips (colorimetric) give a fast estimate; a nitrate meter or lab analysis is more precise, especially near the regulatory limit.

PFAS (PFOA/PFOS 'forever chemicals') · details

No reliable field test exists at these trace (parts-per-trillion) concentrations — samples must be sent to a certified laboratory for LC-MS/MS analysis.

pH · details

pH test strips give a quick field estimate; a digital pH meter is more precise and easy to calibrate.

Turbidity · details

A turbidity tube or handheld NTU meter gives a fast, reliable field reading.

5. Record and log your data

For every sample, note down:

Site name and type (home tap, well, lake, river, trail stream, campsite, other)
Location — a ZIP code at minimum, GPS coordinates if you have them
Date and time of collection
The pollutant tested and the reading, with its unit
Any conditions worth noting (recent rain, visible color/odor, nearby land use)
A photo of the site, if possible

Then head to Submit a Sample and fill in the same details. A moderator will review it — typically within a few days — before it appears on the public map. Approved, well-documented submissions raise your star rating and unlock higher certification levels, which let you report on more sensitive sites with faster review.

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