The DWLCA Standard

1. Eligibility

1. For every method scope requested, the laboratory demonstrates proficiency using EPA-approved methods (40 CFR 141 / EPA-approved alternate test procedures): an initial demonstration of capability for each analyst, acceptable results on a DWLCA-supplied proficiency sample, and a successful onsite observation of the method as run.
2. The laboratory has operated for at least 12 months under its current quality manager, or provides a full quality history from any prior operation.
3. No owner, director, or quality manager has had a laboratory certification revoked for cause in the prior five years.

2. Annual onsite audit

1. A DWLCA assessor conducts an onsite audit within 60 days of initial certification and every 12 months thereafter. Audits are scheduled with 14 days' notice. Certification lapses automatically if an audit is more than 30 days overdue.
2. The audit covers: sample receiving and log-in; storage temperature records; every certified method as performed by the analyst who normally performs it; instrument calibration and maintenance logs; reagent and standard traceability; data review and reporting; and corrective-action records.
3. The assessor traces at least three real customer samples from receipt to final report, end to end.
4. Findings are classed as Observation, Deficiency (30 days to correct), or Critical (immediate suspension of the affected scope until verified corrected).

3. Sample collection and custody

This section is what most distinguishes DWLCA from minimum programs. A perfect analysis of a bad sample is still a bad result.

1. Bottles and preservation. The lab supplies or specifies bottle type, preservative, and volume for every parameter, and documents the lot.
2. Holding times and temperature. Every sample's collection time, receipt time, and receipt temperature are recorded. Samples outside holding time or temperature are flagged on the report — never silently analyzed.
3. Chain of custody. An unbroken, signed custody record from collector to analyst for every sample. Electronic or paper; gaps are a Deficiency.
4. Field collectors. Anyone who collects samples that will carry the DWLCA seal — lab staff, inspectors, contractors — must be trained to the lab's documented collection procedure, and the lab keeps a roster. Labs may enroll collectors in the optional Field Sample Collection Program, which adds field observation to the annual audit.
5. Customer-collected samples are clearly identified as such on the report, with the limitations stated.

4. Proficiency testing

1. The lab participates in a recognized PT provider's studies for every certified scope, at least twice a year, and shares results with DWLCA within 10 days.
2. Blind samples. DWLCA submits unannounced proficiency samples through normal customer channels at least twice per year. A failed blind result suspends the scope pending investigation and a passing re-test.

5. Personnel

1. A named Laboratory Director and Quality Manager (may not be the same person in labs with more than three analysts).
2. Documented initial demonstration of capability and annual continuing demonstration for every analyst, for every method they run.
3. Training records are reviewed at every audit.

6. Quality system

1. A written quality manual covering method SOPs, calibration, QC acceptance limits, corrective action, data integrity, and records retention (minimum 5 years).
2. Method blanks, laboratory control samples, duplicates, and matrix spikes at the frequencies required by the method — with acceptance limits actually enforced.
3. A documented data-integrity policy, signed annually by every employee, including a no-retaliation channel for reporting concerns.

7. Reporting

1. Reports state the method, reporting limit, sample collection date/time, receipt date/time, receipt temperature, and who collected the sample.
2. Any QC failure or holding-time exceedance affecting a result is flagged on the report next to that result.
3. The DWLCA seal and certificate number appear only on reports for scopes the lab is certified for, and only while in good standing.

8. Maintaining certification

1. Certification is valid for 12 months and renews on completion of the annual audit and payment of the renewal fee.
2. The lab notifies DWLCA within 10 business days of any change in ownership, location, Director, Quality Manager, or in any method used for a certified scope.
3. Substantiated public complaints may trigger an unscheduled audit at the lab's expense.

9. Suspension, revocation, and appeal

1. Suspension — a scope or the whole certification is placed on hold, publicly visible, until corrective action is verified. Reinstatement fee applies.
2. Revocation — for falsified data, repeated critical findings, or refusal of audit. Revoked labs are listed publicly for five years and may not reapply for 24 months.
3. Appeal — any decision may be appealed in writing within 30 days to the Council's Appeals Committee, whose members had no part in the original decision. See Governance.

Appendix A — Method scopes

Certification is granted per scope. A lab may hold one or several.

• Inorganic Chemistry
  Turbidity (UR) · Aluminum (UR) · Bromide · Arsenic · Chlorite · Barium · Bromate · Cadmium · Calcium (UR) · Chloride (UR) · Chromium · Copper · Cyanide · Fluoride · Iron · Lead · Magnesium · Manganese · Mercury · Nickel · Nitrate · Nitrite · Orthophosphate (UR) · Selenium · Silica (UR) · Silver (UR) · Sodium · Sulfate · Conductivity (UR) · Alkalinity (UR) · Acidity (UR) · Antimony · Beryllium · Thallium · Total Asbestos · Zinc (UR) · Chrysotile · Amphibole · Color (UR) · Hardness, Total (CaCO3) · Calcium Hardness (as CaCO3) · pH Units (UR) · Alkalinity · TDS - Total Dissolved Solids · Temperature (UR) · Dissolved Organic Carbon (DOC) · Total Organic Carbon (TOC) · UV Absorbance @ 254 nm
• Microbiology
  Heterotrophic Bacteria (HPC) · Enterococci · Fecal Coliform · E. coli · Cryptosporidium (UR) · E. coli Enumeration · Coliform
• PFAS
  PFBS · PFHxS · PFNA · PFOS · PFOA · HFPO-DA (GenX)
• Radiochemistry
  Gross Alpha · Uranium · Radium 226 · Radium 228 · Gross Beta · Tritium · Strontium 89 · Strontium 90 · Iodine 131 · Cesium 134 · Radon in Water
• Synthetic Organic Chemicals (SOC)
  Endrin · Lindane · Methoxychlor · Toxaphene · Dalapon · Diquat · Endothall · Glyphosate · Di-2(ethylhexyl)adipate · Oxamyl · Simazine · Di(2-Ethylhexyl) Phthalate · Picloram · Dinoseb · Hexachlorocyclopentadiene · Carbofuran · Atrazine · Alachlor · Dioxin (2,3,7,8-TCDD) · Heptachlor · Heptachlor Epoxide · 2,4-D · 2,4,5-TP (Silvex) · Hexachlorobenzene · Benzo(a)pyrene · Pentachlorophenol · Polychlorinated biphenyls (PCB) · Monochloroacetic acid · Dichloroacetic acid · Trichloroacetic acid · Monobromoacetic acid · Dibromoacetic acid · Total Haloacetic Acids · 1,2-Dibromo-3-Chloropropane · Ethylene dibromide (EDB) · Chlordane
• Volatile Organic Chemicals (VOC)
  1,4-Dioxane (UR) · 1,2,4-Trichlorobenzene · cis-1,2-Dichloroethylene · Chloroform · Bromoform · Bromodichloromethane · Chlorodibromomethane · Total Trihalomethanes · Total Xylenes · Dichloromethane · 1,2-Dichlorobenzene · 1,4-Dichlorobenzene · Vinyl Chloride · 1,1-Dichloroethylene · trans-1,2-Dichloroethylene · 1,2-Dichloroethane · 1,1,1-Trichloroethane · Carbon Tetrachloride · 1,2-Dichloropropane · Trichloroethylene · 1,1,2-Trichloroethane · Tetrachloroethylene · Chlorobenzene · Benzene · Toluene · Ethylbenzene · Styrene
• Field Sample Collection Program
  Collector training & roster · Bottle/preservative kits · Temperature & holding-time logging · Chain of custody in the field