North Water District Laboratory Services, Inc. is an environmental laboratory in Conroe, Texas, United States. NWDLS provides superior service and quality analysis for inorganic and organic constituents in tissue, aqueous, and solid matrices for engineering firms, municipalities, school districts, government agencies, industrial facilities, and individuals in the Greater Houston area for forty years. We are certified with the State of Texas as a Historically Underutilized Business (HUB), with the City of Houston as a Woman-Owned Business, and have been a NELAP accredited laboratory since 2008.