Sources and method
Each listing comes from the official file below. We store the raw file with its fetch date and checksum, parse it into rows, and link every lab page back to it.
| State | Listings | Format | Version | Official list |
|---|---|---|---|---|
| Connecticut | 17 | PDF table (+ commercial-lab PDF for addresses) | 10/09/2026 | CT DPH In-State Approved Commercial Laboratories Certified to Test Drinking Water |
| Minnesota | 23 | PDF map + table (private-well labs only) | October 2026 | MDH Accredited Labs in Minnesota Accepting Drinking Water Samples from Private Well Users |
| Vermont | 46 | PDF table with embedded per-lab scope sheets | September 28, 2026 | Vermont Department of Health - Laboratories Certified for Drinking Water Analysis |
| Maine | 12 | 1-page PDF (in-state commercial labs) | Last updated 5/16/2026 | Maine In-State Commercial Drinking Water Labs |
| Ohio | 75 | PDF (combined lab list) | November 2026 | Ohio EPA - Laboratories Certified/Accepted to Perform Analyses on Public Drinking Water |
| Wisconsin | 135 | HTML table (coliform bacteria labs) | live page | Wisconsin DNR - Drinking Water (SDWA) Labs Certified for Coliform Bacteria Testing |
| Virginia | 146 | XLSX, analyte-level | Current as of 8/1/2026 | Virginia DCLS - Drinking Water Certified Labs (analyte detail) |
| Washington | 91 | PDF with per-lab drinking-water scopes + Lab Search 'accepts public samples' | Information current as of 11/13/2026 | WA Ecology - Environmental Laboratories Accredited for Drinking Water Analyses (with scopes) |
| Pennsylvania | 169 | PDF bulk reports, analyte-level (June 2024: STALE) | STALE - report dated 6/11/2024 | PA DEP Accredited Labs Report - Drinking Water (chemistry + microbiology) |
| New York | 39 | HTML table (PFAS methods 533 / 537.1 only) | page fetched 2026-10-29 | NY DOH - New York State accredited labs for PFOA/PFOS (EPA 533 / 537.1 v2), private-well rebate program |
| Massachusetts | 36 | XLSX (labs offering / not offering residential services) | Created and published on 12/18/2025 | MassDEP Certified Laboratories Offering Analytical Services for Private Well Owners and Residential Customers |
| 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 | California ELAP - Accredited Laboratories (map layer) + per-lab Fields of Accreditation |
| Missouri | 89 | XLSX, analyte-level (chemical); lab-level (microbiological) | Live export fetched 2026-11-15 (no list date printed in the file) | Missouri DNR - Certified Chemical Laboratories (spreadsheet of all laboratories) |
| 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) | TDEC Division of Water Resources - Commercial Laboratories Certified for Drinking Water Analysis + TDEC Division of Water Resources - Microbiological Laboratories Certified for Drinking Water Analyses |
| Georgia | 43 | PDF lists (chemical, microbiological, lead and copper, PFAS), lab-level | January 9, 2025 | Laboratories Certified by Georgia for Chemical Monitoring + Laboratories Certified by Georgia for Lead and Copper Monitoring + Laboratories Certified by Georgia for PFAS Monitoring |
| Alabama | 64 | 4 PDF lists, lab-level (bacteriological, in-state chemical, out-of-state chemical; PFAS by EPA 537.1) | Revised: April 7, 2026 | ADEM - Certified Bacteriological Laboratories |
| 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) | EGLE - State of Michigan Certified Laboratories: Chemistry + EGLE - State of Michigan Certified Laboratories: Microbiological + EGLE - State of Michigan Certified Laboratories: Lead and Copper + EGLE - Certified Radiological Laboratories + EGLE - In-State Certified PFAS Laboratories |
| 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 | IEPA Accredited Laboratories (Primary Labs / Secondary Labs) - Laboratories Accredited for Chemical Analysis + TNI LAMS fields of accreditation (Drinking Water, accrediting body IL ELAP) |
| 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) | Iowa DNR LabCert - List of Certified Labs (Drinking Water program) + Find a Lab analyte search + Lab Details |
| 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) | Florida DOH - Laboratories Certified Under NELAP (DEP Qlik app): Analyte Search + Organization Name and Location Search, Matrix = Drinking Water, Certification Status = Accredited, Active labs |
| 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") | TCEQ Laboratory Approval Status - List of Accredited Laboratories (public database, Matrix: Drinking Water) |
| Louisiana | 49 | PDF x2 (chemistry: per-lab scopes, analyte-level; microbiology: lab list with methods) | Current as of 2/12/2026 | LDH - 2026 List of Laboratories Certified by Louisiana for Drinking Water Analyses - Chemistry |
| Oklahoma | 31 | Searchable database (ODEQ Lab Facility Search), report export (Excel/PDF), matrix Drinking Water, analyte-level | Live database, searched 2026-11-02 | ODEQ Lab Facility Search - laboratories accredited by the DEQ Laboratory Accreditation Program (Matrix: Drinking Water) |
| 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") | NDEP Laboratory Approval Status - Certified Lab List (public database, Matrix: Drinking Water) |
| 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) | EPA Region 8 Certified Drinking Water Laboratories in Wyoming |
| Hawaii | 19 | PDF x2: chemistry/radiochemistry matrix (analyte x lab, methods, certification dates) + microbiology table (methods, expiry) | August 12th, 2026 | Hawaii DOH State Laboratories Division - Certified Chemistry & Radiochemistry Drinking Water Labs |
| 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 | Water Supply Certification: In-State Labs (Participating Laboratories) |
| 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') | Laboratories certified for the analysis of drinking water in the state of South Dakota |
| 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) | CDPHE Drinking Water Lab Certifications (Looker Studio report on cdphe.colorado.gov/dwlabs) |
| 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") | KDHE Approved Laboratory Search (AB Manager public database, Matrix: Drinking Water) |
| 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 | Maryland's Certified Drinking Water Laboratories (MDE Laboratory Certification Program) |
| 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 | WV OLS Environmental Drinking Water Laboratory Certification Program - Laboratory Certified Parameter 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 | NC SLPH Environmental Sciences - Certified Drinking Water Laboratories (Commercial) |
| 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 | ADHS Safe Drinking Water Commercial Lab List (List of Arizona Certified Commercial Drinking Water Laboratories) |
| 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) | Montana DPHHS Water Laboratory Certification Program - Certified Laboratories |
| 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 | Alaska DEC - Laboratories Certified to Perform Microbiological Analyses of Drinking Water |
| 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 | Departamento de Salud de Puerto Rico, Sección de Agua Potable - Laboratorios y Parámetros Certificados |
| 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) | ORELAP laboratory search (ODIE): accredited for the Drinking Water matrix |
| 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 | IDOH Water Test Facilities Application (in-state drinking water laboratories) |
| 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 | RIDOH - Certified Drinking Water Testing Labs / RIDOH - Appendix to Analytical Laboratory Certificate LAI00368 |
| 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) | Nebraska DHHS - Certified Laboratories (drinking water) |
| 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 | 2026 KY Certified Drinking Water PFAS Laboratory 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) | SCDES Commercial Environmental Laboratory Mapping (CELMAPP) - certified commercial laboratories, Safe Drinking Water |
| 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 | Laboratories Certified by NMED-DWB to Analyze Drinking Water Samples for Water Systems in New Mexico |
| 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 | Idaho Bureau of Laboratories - EPA Region 10 Drinking Water Certificates |
Rules we follow
- Certification fields (lab name, ID, analytes, expiry, homeowner flag) come only from the state list. Nothing is inferred by a model.
- If the list doesn't publish a field, we leave it blank and say so.
- Group-level certifications are labelled as such: confirm the specific analyte and method with the lab.
- We publish business details only. We drop personal names (lab directors, contacts) that appear on some lists.
- A listing is not an endorsement. Status can change between list updates.
Figures on lab, county and hazard-lab pages
| Figure | Source | Period | We refresh it |
|---|---|---|---|
| People on private wells per county | USGS, estimated use of water in the United States, county data | 2015 | When USGS publishes a newer county table |
| Private-well users with arsenic above 10 µg/L | USGS, Ayotte, Medalie and Qi (2017) | 2010 population base | Static model estimate |
| Radon zone | EPA map of radon zones | 1993 map | Static |
| PFAS in public water systems | EPA UCMR 5 occurrence data | 2023–2026 samples | When EPA posts a new file (quarterly) |
| Homes built before 1980 | Census Bureau, ACS 5-year table B25034 | 2020–2024 | Each December release |
| Homeowner samples, prices, turnaround | Each lab’s own website, read twice | Date shown on the page | Every 90 days |
| Nearest labs and distances | Our calculation: straight line between the addresses (or ZIP-code centres) on the official lists | Current lists | Every build |
| Changes on a lab’s certification | Our comparison of the current and previous version of the state list | Dates shown | Weekly |
Journalists and researchers who need the compiled list can request the data. Who runs the site and how pages are checked: about WaterListed.
National entry point: U.S. EPA, state certification programs for drinking-water labs.