State-certified labs · 3361 listings · 45 states
Find the lab that tests your well.
Every lab here comes from an official state certification list, and we show which tests the state says it can run. Pick your state and the contaminant you're worried about.
Pick your state, then the test.
45 states are in so far, with 2291 distinct labs. Tap a state on the map to see its list, or use the filters below.
Near ZIP sorts labs by straight-line distance from the middle of that ZIP. Your ZIP stays in your browser; the page loads a small data file for its first three digits. Check my ZIP also shows your county's data.
About the filters: "Accepts samples from the public" shows only labs the state marks as taking private-well or public samples. Only CT, MN, VT and WA publish that (WA's label is "Accepts Commercial/Public Samples"). Group-level means the lab holds the parent certification (for example "Inorganics"), so confirm the specific test with the lab. For your county's private-well data and the nearest labs in one place, check your ZIP.
Certified means listed by the state.
We parse each state's own list and keep the file it came from. The certification fields come only from those lists, never from a model or a lab's marketing.
See every source and list version
| State | Listings | Source format | List version | Source |
|---|---|---|---|---|
| Connecticut | 17 | PDF table (+ commercial-lab PDF for addresses) | 10/09/2026 | Official list |
| Minnesota | 23 | PDF map + table (private-well labs only) | October 2026 | Official list |
| Vermont | 46 | PDF table with embedded per-lab scope sheets | September 28, 2026 | Official list |
| Maine | 12 | 1-page PDF (in-state commercial labs) | Last updated 5/16/2026 | Official list |
| Ohio | 75 | PDF (combined lab list) | November 2026 | Official list |
| Wisconsin | 135 | HTML table (coliform bacteria labs) | live page | Official list |
| Virginia | 146 | XLSX, analyte-level | Current as of 8/1/2026 | Official list |
| Washington | 91 | PDF with per-lab drinking-water scopes + Lab Search 'accepts public samples' | Information current as of 11/13/2026 | Official list |
| Pennsylvania | 169 | PDF bulk reports, analyte-level (June 2024: STALE) | STALE - report dated 6/11/2024 | Official list |
| New York | 39 | HTML table (PFAS methods 533 / 537.1 only) | page fetched 2026-10-29 | Official list |
| Massachusetts | 36 | XLSX (labs offering / not offering residential services) | Created and published on 12/18/2025 | Official list |
| California | 304 | ArcGIS map layer (JSON) + per-lab Fields of Accreditation PDFs, analyte-level | Map layer fetched 2026-11-15; scope PDF as of 6/8/2026 | Official list |
| Missouri | 89 | XLSX, analyte-level (chemical); lab-level (microbiological) | Live export fetched 2026-11-15 (no list date printed in the file) | Official list |
| Tennessee | 150 | PDF x2 (commercial labs: certified contaminant groups; microbiological labs: method groups) | 10/2/2026 (page footers 10/06/2026); As of October 2, 2026 (PDF title; page footers 10/06/2026) | Official list |
| Georgia | 43 | PDF lists (chemical, microbiological, lead and copper, PFAS), lab-level | January 9, 2025 | Official list |
| Alabama | 64 | 4 PDF lists, lab-level (bacteriological, in-state chemical, out-of-state chemical; PFAS by EPA 537.1) | Revised: April 7, 2026 | Official list |
| Michigan | 212 | 8 PDF lists, analyte-level (chemistry, microbiological, lead and copper, out-of-state, radiological, in-state PFAS, out-of-state PFAS, Cryptosporidium) | SOM Certified Labs - Chemistry 3/11/2026 (chemistry, microbiological, lead and copper lists); 9/8/2025 (radiological, in-state PFAS lists) | Official list |
| Illinois | 96 | PDF x2 (IEPA chemistry list; IDPH microbiology list with methods per lab) + TNI LAMS drinking-water scope per chemistry lab, analyte-level | 12/09/2025 (date in the file name; the PDF prints no date); TNI LAMS as fetched 2026-11-15 | Official list |
| Iowa | 58 | LabCert web application: certified-lab table (Excel export) + per-analyte search, analyte-level (Drinking Water program) | Date Generated: 11/14/2026 (LabCert, live database) | Official list |
| Florida | 222 | Qlik Sense app (DEP-hosted, DOH data, refreshed weekly): Export Table of the Analyte Search with Matrix = Drinking Water + Organization Name and Location Search, analyte-level | DOH Version: 11/07/2026 08:30:01 (Qlik app refresh 11/9/2026 4:26:47 AM; live database) | Official list |
| Texas | 144 | Searchable database (AB Manager), CSV exports: accredited parameters (matrix Drinking Water) + lab contacts, analyte-level | Live database, searched 2026-11-15 ("accurate as of the date and time of the search") | Official list |
| Louisiana | 49 | PDF x2 (chemistry: per-lab scopes, analyte-level; microbiology: lab list with methods) | Current as of 2/12/2026 | Official list |
| Oklahoma | 31 | Searchable database (ODEQ Lab Facility Search), report export (Excel/PDF), matrix Drinking Water, analyte-level | Live database, searched 2026-11-02 | Official list |
| Nevada | 58 | Searchable database (AB Manager), CSV exports: certified parameters (matrix Drinking Water) + lab contacts, analyte-level | Live database, searched 2026-11-15 ("accurate as of the date and time of the search") | Official list |
| Wyoming | 12 | 1-page PDF matrix, analyte-level (inorganics, disinfection byproducts, microbiology, radionuclides, synthetic organics, VOC) | Current as of February 2026 (page footer 2/17/2026) | Official list |
| Hawaii | 19 | PDF x2: chemistry/radiochemistry matrix (analyte x lab, methods, certification dates) + microbiology table (methods, expiry) | August 12th, 2026 | Official list |
| Mississippi | 5 | HTML list, in-state labs only: EPA lab ID and certification category (Chemistry, Microbiology) per lab; no analytes, no expiry | undated page; MSDH site data shows it updated Oct 10, 2026 | Official list |
| South Dakota | 16 | HTML list (in-state labs + other labs certified by South Dakota): 'Certified for' analyte groups per lab (e.g. Inorganics, VOC's, Microbiology, E.Coli enumeration, Lead, Copper, Uranium, PFAS); no expiry, no cert numbers | undated (the page shows only 'Copyright © 2026') | Official list |
| Colorado | 94 | Interactive report (Google Looker Studio, 'Drinking Water Lab Certifications') on CDPHE's page: one row per lab, analyte and method, with lab status (Active/Expired), city/state/ZIP and 'Accepts Outside Samples'; analyte-level; no street address, phone or expiry date | Live report, no edit date shown; data read by the report at 2026-11-02 20:39 UTC (Looker Studio dataTimestamp) | Official list |
| Kansas | 47 | Searchable database (AB Manager), CSV exports: accredited parameters (matrix Drinking Water) + lab contacts, analyte-level | Live database, searched 2026-11-15 ("believed to be accurate at the time of the search") | Official list |
| Maryland | 92 | PDF list (7 pp): MD certification number and approved test groups per lab (codes keyed to MDE's 'List of Approved Contaminants'), plus MDE's PFAS list (EPA 533 / 537.1 per lab); no expiry dates | Latest Revisions: 10/1/2026 | Official list |
| West Virginia | 50 | PDF (~100 pp): one 'Laboratory Certified Parameter List' per certificate - analyte, method and status (Certified / Interim / Not Certified), certificate number, issue and expiration date; chemistry and microbiology certificates in one file | printed Thursday, August 20, 2026 | Official list |
| North Carolina | 238 | HTML lists (Commercial; Health Departments/Municipalities): city, lab name, NC lab number and phone per lab, plus each lab's detail page with the contaminants it is certified for; no list date printed | generated on request (no date printed), fetched 2026-11-07 | Official list |
| Arizona | 51 | HTML list ('Safe Drinking Water Commercial Lab List', updated every 24 h): lab name, city, state and phone per licensed location; per-lab AZ license number, address and Safe Drinking Water parameters from ADHS's 'with Parameters' view | current as of Saturday, November 7, 2026 | Official list |
| Montana | 36 | HTML list on the program page: labs by certification category (Chemistry - Asbestos; Chemistry - Inorganic and Organic; Chemistry - Inorganic only; Radiologic only; Microbiology), Montana and out-of-state; no analytes, certificate numbers or expiry dates | page as fetched 2026-11-15 (no date printed) | Official list |
| Alaska | 26 | Two HTML pages (microbiology, chemistry): per lab the certification number, expiry date and every method x analyte with its status (Fully / Provisionally Certified) | page as fetched 2026-11-03 (no date printed); chemistry page not available | Official list |
| Puerto Rico | 12 | PDF list (1 page, Spanish): lab, address, phone and the groups each lab is certified for (Bacteriología, Químicos, Radiológicos; 'Reciprocidad' for out-of-island labs); no analytes, certificate numbers or expiry dates | Revisado agosto 2025 | Official list |
| Oregon | 92 | ORELAP's online lab search (ODIE: Drinking Water matrix, 'Accepts Public Samples' filter) plus each lab's ORELAP Fields of Accreditation (certificate, expiry, every drinking-water method x analyte) | search as fetched 2026-11-15 (live database, no list date) | Official list |
| Indiana | 74 | In-state labs: IDOH's 'Water Test Facilities Application' map (certified tests and tests offered per lab, no certification numbers or expiry); out-of-state labs: table on the program page (Lab ID, certified analytes); radiochemistry labs: a second table on the program page | layer data edited 2026-08-17 | Official list |
| Rhode Island | 43 | HTML list of certified drinking-water labs in and near Rhode Island, RIDOH's certificate appendix per in-state lab (every certified analyte and method, expiry date), and a PDF list of out-of-state labs (address, certificate number, certification categories only) | page as fetched 2026-11-07 (no date printed); certificate appendix issued 1/21/2026 | Official list |
| Nebraska | 5 | PDF table (1 page): NE certification number, address and the certified analytes with their methods per lab; no phone numbers or expiry dates | no date printed; PDF created 2024-05-22 (file metadata) | Official list |
| Kentucky | 14 | 1-page PDF table (PFAS-certified labs only): Lab ID, Micro / Chem / PFAS marks, mailing address, lab phone; no expiry | Revised 1/23/2026 | Official list |
| South Carolina | 49 | SCDES's CELMAPP map service (ArcGIS): certified commercial laboratories with SC permit number, address and phone, and each lab's certified Safe Drinking Water parameters and methods; no list date (data refresh date shown) or expiry dates | no date printed; CELMAPP data last refreshed 2026-10-10 (LastRefreshDate of SCDES's details table) | Official list |
| New Mexico | 44 | PDF table (1 p): NM certification number, analyte-group codes (legend on the page), city/state, expiry date, phone and NMED-DWB contract flag per lab; no street address | Last Updated: 10/26/2026 | Official list |
| Idaho | 33 | Scanned per-lab certificates in DHW's public document library (one PDF per lab and discipline: inorganic, organic, microbiology, radiochemistry; analyte, status and method per lab, effective dates), read by OCR and checked line by line | 2026 EPA Region 10 Drinking Water Certificate Microbiology LT2: letter of January 22, 2026; 2025 EPA Region 10 Drinking Water Certificate Chemistry: letter of March 24, 2025; 2025 EPA Region 10 Drinking Water Certificate Microbiology: letter of May 23, 2025 | Official list |
What to test first, and why.
Federal limits apply to public water systems, not private wells. They're still the usual yardstick for well results.
Nitrate in well water
Comes from fertilizer, septic systems and manure. Most serious for infants under six months.
Read the explainer 2266 listings test for it 0MCLG for total coliformsColiform bacteria and E. coli
An indicator test. A positive result means surface water or waste may be reaching the well.
Read the explainer 838 listings test for it 0.010mg/L (10 ppb, EPA MCL)Arsenic in well water
Often natural, from rock and soil. You can't taste it, so only a lab test will tell you.
Read the explainer 986 listings test for it 15µg/L (ppb) EPA action level, public systemsLead in well water
Mostly comes from household plumbing, not the aquifer. No known safe level in a child's blood.
Read the explainer 558 listings test for it 4.0ng/L (ppt) EPA MCL for PFOA and PFOS, public systemsPFAS in well water
Man-made 'forever chemicals'. EPA sets limits for public systems only and gives no standard for private wells.
Read the explainer 425 listings test for it 30µg/L EPA MCL, public systemsUranium in well water
Occurs naturally in some rock and soil. Kidney effects are the main concern at high levels.
Read the explainer 58 listings test for it 4pCi/L in indoor air: EPA's level to fix a homeRadon in well water
A gas from rock and soil. In most homes the air is the larger risk, and water is the second thing to check.
Read the explainer 569 listings test for it 0.05mg/L EPA secondary (aesthetic) standardManganese in well water
Stains and tastes bad at low levels. EPA also publishes health advisory values, with extra caution for infants.
Read the explainer 516 listings test for it 0.005mg/L (5 µg/L) EPA MCL for benzene, TCE, PCE; public systemsVOCs (solvents, fuel compounds) in well water
Industrial solvents and fuel-related compounds. Rare in most wells, but worth a test near sources.
Read the explainer ExplainerCopper in well water: why it comes from your pipes, what 1.3 mg/L means, and how to test it
On a private well, copper almost always comes from the plumbing, and corrosive water or new copper pipe decides how much. A first-draw and a flushed sample from the same faucet show whether running the water is enough or the water itself needs treating.
Read the explainer ExplainerE. coli in well water: what a positive means and what to do today
An E. coli positive means human or animal waste is reaching your well. Here is the household checklist for today, the people who need a doctor's advice, how to trace the source this week, and the retest schedule state and federal agencies give.
Read the explainer ExplainerFluoride in well water: the two federal limits, how to test, and what your number means for children
Most U.S. domestic wells have less fluoride than the 0.7 mg/L dental benchmark, and a few have more than EPA's 2.0 and 4.0 mg/L levels. One lab test tells you which, and your child's dentist needs that number either way.
Read the explainer ExplainerSalt in well water: sodium, chloride and sulfate, where they come from and what the numbers mean
"Salt" on a well report is three results: sodium, chloride and sulfate. Each has its own EPA guideline, none enforceable on a private well, and each points to different sources, from road salt and softeners to seawater and rock.
Read the explainer ExplainerSediment in well water: what sand, silt or mud means, and when it calls for a bacteria test
Most grit in well water is a nuisance that points to the well, the pump or the water's chemistry. Water that turns muddy after heavy rain is different: it can mean surface water is getting in, so test for coliform bacteria first.
Read the explainerTest your well every year.
EPA advises private-well owners to test annually for total coliform bacteria, nitrates, total dissolved solids and pH, and for other contaminants if they suspect them. Use a state-certified lab, and check that it runs the test you need.
Source: U.S. EPA, Protect your home's water