National Park Service Mammoth Water Quality Control Lab

At a glance

What it is certified to test

1 of the 9 common well tests on the WY list (see which)

Price

not published on the state list: ask the lab for a quote

Turnaround

not stated on the state list or the lab’s website: ask when you order

Homeowner samples

not stated: ask the lab

Lab facts

Listed by

Wyoming (U.S. EPA Region 8 - Drinking Water Laboratory Certification (Wyoming has no state drinking-water program of its own: EPA Region 8 runs it and certifies Wyoming's labs))

Address

PO Box 168, Mammoth Hot Springs, WY 82190 · Open in Google Maps

Public / homeowner samples

Public samples: ask the lab

Not stated in the list.

Left blank on the list

The Wyoming list (version Current as of February 2026 (page footer 2/17/2026)) gives no phone, website for this lab.

Certification record

Issued by

U.S. EPA Region 8 - Drinking Water Laboratory Certification (Wyoming has no state drinking-water program of its own: EPA Region 8 runs it and certifies Wyoming's labs) (certification program)

Expiry on the list

12/31/2028 · expires in about 25 months

List version

EPA Region 8 Certified Drinking Water Laboratories in Wyoming, version Current as of February 2026 (page footer 2/17/2026)

We fetched it

15 Nov 2026 (file SHA-256 04cbb22d4cdc…) · open the state file

Tests on the state list

• Named on the official list The state list names this analyte (or a column for it) for this lab.
• Group-level certification Certified for a parent group (e.g. 'Inorganics') that includes this analyte. Confirm the specific test with the lab.
• Partial group certification The list marks the group as 'Partial'. Confirm this analyte with the lab.
• Subcontracted The lab sends this analyte to another accredited lab (MDH 'X*').

EPA's list prints a phone number only as part of a staff contact's details, so no phone is shown.

Nearest labs that take homeowner samples

No other lab that takes homeowner samples is within 25 miles of this lab; the nearest is 72 miles away. Distances are straight-line from the address on the state list (approx. = ZIP-code centre). “Takes homeowner samples” comes from a state list column or the lab’s own website, as named.

Price and turnaround as printed on each lab’s own website and checked by a second reader; – = not published or not read yet.

Around this lab: Park County, WY

• Private wells: about 5,941 people, 20% of Park County’s 29,228 residents (USGS, 2015); rank 6 of 23 counties in Wyoming by people on wells.

• EPA radon zone (indoor air): Zone 1: highest potential (average indoor radon may be greater than 4 pCi/L). EPA says the zone map should not decide whether one home needs testing.
• Arsenic above 10 µg/L (USGS model): about 332 private-well users (95% range 268 to 420; 2010 base), rank 5 of 23 in the state. A screening estimate, not a measurement of any well.
• Older homes (Census ACS 2020–2024): 46% of 14,989 housing units were built before 1980, below the state share of 49%. Homes built before 1986 are more likely to have lead solder or fittings, so test tap water for lead there.
• PFAS in public water nearby (public supply, not your well): 5 public systems serving this county reported EPA UCMR 5 results; 0 had a PFOA or PFOS sample at or above 4.0 ng/L.

County figures describe where the lab is, not the lab. Sources: USGS 2015 water use and 2017 arsenic estimates, EPA radon zones, Census ACS table B25034 (2020–2024), EPA UCMR 5 (2023–2026); details and links on the sources page.

Before you send a sample

Call the lab to confirm it's currently certified for the exact test and method, that it accepts samples from homeowners, and how to collect and ship them. Bacteria samples have short holding times. Status can change between list updates. To check a status, contact the Wyoming certification program.

Is this your lab?

Labs can ask for corrections through the agency that publishes their state list. Homeowner service, prices and turnaround above come only from the lab’s own website. To ask us to correct or remove this listing, write to us (how we handle listings).