Gold Partner

750 Royal Oaks Dr Monrovia CA
United States - 91016
Phone: (626) 386-1100

Our Company


About Us


Accurate, cost-efficient water and wastewater analyses are vital to your enterprise. For over 30 years, water industry professionals worldwide have relied on MWH Laboratories for the fast, reliable data they need. Now, we're committed to proving our value to you.

When you engage MWH Labs, you gain the services of one of the most seasoned and highly regarded water/wastewater analysis laboratories in the nation. Your tests are performed by specialized scientists in state-of-the-art facilities custom-designed to our exacting standards.

As the largest potable and recycled water focused laboratory in the country, MWH Labs is your comprehensive source for a wide array of capabilities, ranging from low-level drinking water analyses to leading-edge work with emerging contaminants like nitrosamines and endocrine disruptors.

Expert consultation on your results is a key part of our service to you. So is access to our exceptional wealth of regulatory expertise - knowledge amassed over years of extensive work with state, federal, and local regulatory groups.

Today, over 100 of the largest municipalities in the United States look to MWH Labs for precise, reliable, and timely data. So do hundreds of utilities, engineering firms, laboratories and private industries across the nation and around the world.

We look forward to putting our powerful resources to work for your enterprise.

Full-Service Capabilities

MWH Labs is your single source for a broad range of consistently high-quality water and wastewater tests analyzing for disinfection byproducts, microbiology, organics, inorganics, asbestos and radioactivity.

You can look to us for reliable low-level analyses related to potable water regulations and recycled water testing, performed using equipment uncompromised by analysis of contaminated hazardous waste samples. When you need sophisticated microbiology testing and full-service chemical and specialized radiochemical analysis for your potentially potable water, we're the only commercial lab in the country equipped to handle it for you in-house.




When you choose MWH Laboratories, you gain access to an extensive array of services no other US commercial lab focused on potable and recycled water provides.

Organic analysis including synthetic organic chemicals by GCMS and GC, pesticides and herbicides by GC and HPLC, volatile organics (VOCs) by GC and GCMS, taste and odor compounds such as MIB and Geosmin, and nitrosamines (NDMA and NDEA) to ppt levels.

Drinking water synthetic organic and volatile organic tests including EPA Methods 504.1 (EDB and DBCP, 505 (Pesticides and PCBs), 515.4 and 555 (Herbicides), 524.2 (VOCs and Epichlorohydrin), 525.2 (Synthetic Organics), 526 (Synthetic Organics, 528 (Phenolics), 531.1 and 531.2 (Carbamates), 547 (Glyphosate), 548.1 (Endothall), 549.2 (Diquat) and 6040 (MIB-Geosmin and Anisoles), 1625 and 521 (NDMA and NDEA).

Recycled water tests including 601/602 (Volatiles), 608 (Pesticides and PCBs), 624 (Volatiles), and 625 (Semivolatiles).

Organic disinfection byproduct and precursor analyses including aldehydes (Standard Methods 6252); cyanogen chloride (524.2); chloral hydrate (551.1), haloacetonitriles and haloketones (551.1), haloacetic acids (Standard Methods 6251B); trihalomethanes (524.2, 551.1) and SDS determinations (Standard Methods 5710); TOC (5310C, 415.3); DOC (5310C, 415.3); UV (5910B, 415.3); SUVA (IESWTR, 415.3); and BDOC (Allgeier).

Inorganic disinfection byproducts and precursors including bromate (300.1) to levels of 1 ppb (317), chlorite and chlorate (300.1), and bromide (300).

Inorganic tests including a complete suite of metals to low-reporting levels, using methods 200.7, 200.8, 200.9, 245.1, and 218.6 (or approved equivalent methods).

Other inorganic tests include nutrients, anions, asbestos, perchlorate, and general mineral analysis, using a variety of methods.

Microbiological analyses include coliform, HPC, enterococci, AOC, viruses, and coliphage. Protozoan testing using 1623 or the ICR method are available through our partners specializing in these tests.

Radiochemical analyses available in-house include alpha/beta (900), radium-228 (904), tritium (906), uranium (200.8), and radon (SM7500).


State Certifications


Every assignment you entrust to us will be performed to the highest possible standards. MWH Laboratories meets the stringent certification requirements of over 40 states and territories, and is accredited by the National Environmental Laboratory Accreditation Program (NELAP). Our Quality Assurance program is modeled after ISO17025, an internationally accepted program.

List of certified states includes:

Alaska (AK)
Alabama (AL)
Arizona (AZ)
California (CA)
Colorado (CO)
Connecticut (CT)
Delaware (DE)
Florida (FL)
Georgia (GA)
Hawaii (HI)
Idaho (ID)
Illinois (IL)
Indiana (IN)
Kansas (KS)
Kentucky (KY)
Louisiana (LA)
Maine (ME)
Massachusetts (MA)
Maryland (MD)
Michigan (MI)
Montana (MT)
Mississippi (MS)
New Hampshire (NH)
North Carolina (NC)
North Dakota (ND)
New Jersey (NJ)
New Mexico (NM)
Nevada (NV)
New York (NY)
Oregon (OR)
Pennsylvania (PA)
Rhode Island (RI)
South Carolina (SC)
South Dakota (SD)
Tennessee (TN)
Texas (TX)
Utah (UT)
Virginia (VA)
Vermont (VT)
Washington (WA)
Wisconsin (WI)
West Virginia (WV)
Wyoming (WY)

Additional Certifications

  • UCMR CLO4 Approval
  • Massachusetts CLO4 Approval
  • UCMR Aeromonas Approval
  • (WV) Air Force
  • All - EPA ICR Approval
  • Radioactive Material License - CA
  • Los Angeles County Permit/License to Operate
  • LA County Sanitation District Certification
  • CA Permit to receive soils from foreign sources
  • Alternative Test Procedure (ATP) Method Approval
  • Inland Empire Service Center/Laboratory certified by California Department of Health Services (CA2641)

For additional information on any state click here


QA Overview


MWH maintains a comprehensive Quality Assurance and Quality Control Program. Our QA/QC policies and procedures aim to measure quality in terms of precision, accuracy, completeness, representativeness, comparability, timeliness and documentation across each and every area of the operation, and are based on having a stringent Quality System in place in accordance with National Environmental Laboratory Accreditation Program (NELAP). Key aspects of the program include proactive use of Quality Investigation Reports (QIRs) to identify and respond to potential problems with our quality system, internal data audits, and frequent proficiency testing (PT) with consistent high scores, including the use of Corrective Action Proficiency Testing (CAR) whenever a potential problem is identified in a PT sample. The program focuses on all aspects of the collection, analysis, and reporting process.

  • Sample Collection and Handling procedures aim to sustain original sample integrity and mitigate matrix interferences from the time of collection until delivery to the laboratory.
  • Sample Custody procedures aim to identify unusable samples (for analysis) and meticulously document sample acceptance and transport at login, storage, analysis and disposal.
  • Sample Analysis procedures aim to maintain consistency in the application of methods for media/reagent preparation, extraction, analysis, detection limits, instrument calibration frequency and acceptance criteria, data reduction and reporting.
  • Sample Data Integrity procedures aim to establish corrective action and response guidelines for addressing instrument failures and analytical results that do not meet the required standards.
  • Sample Reporting procedures aim to produce analytical deliverables that meet or exceed project requirements as specific by Federal and State regulatory agencies.

Our comprehensive QA/QC Program is subject to annual on-site inspections and/or has been approved by many Federal and State Agencies, including the United States EPA, United States Air Force, California DHS (NELAC), Arizona DHS, and over 40 other state agencies and private entities. We strive to ensure that our MRLs are significantly below requirements wherever feasible to ensure that values reported are quantitative in nature rather than merely representing detects.


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Bromate Analysis

MWH Labs has been providing bromate analysis by method 317.  This method is generally free from the positive or negative interferences associated with method 300.1, the conventional method for bromate.   As of M

IDSE Analysis

MWH Labs provides comprehensive analytical support for Initial Distribution System Evaluation (IDSE) monitoring.    High capacity for both HAA and THM analysis, to ensure that you can get your sampling done when

Phase II/V Analysis

Organic contaminant tests performed include 504 (EDB/DBCP), 505 (Pesticides), 524 (Volatiles), 515 (Herbicides), 525 (SOCS and Pesticides), 531 (Carbamates), 547 (Glyphosate) , 548 (Endothall), and 549 (Diquat). MWH Labs

Taste And Odor Analysis By Automated SPME

MWH Labs provides analysis of MIB and Geosmin in potable water samples using solid phase micro-extraction (SPME). MWH has been performing MIB-Geosmin analysis for clients across the United States over 10 years, and co-au

UCMR2 Analysis

MWH was the first laboratory to submit a data package for UCMR2 testing.  We are prepared to support you for all of the required UCMR2 methods, including 527, 529, 331, 521, 525, and 535.   In UCMR1 we performed


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