Profile: National Testing Laboratories, Ltd. is a provider of laboratory services in support of environmental health and safety issues. Our Watercheck 1 & 2 includes heavy metals & minerals, other inorganic chemicals, and physical characteristics. The City-Check Basic testing package is developed for homeowners who are concerned about the water quality they are getting from their municipal supply. This package covers the basic contaminants which are likely to be found in municipal drinking water supplies. This includes 5 metals/minerals, 6 inorganic compounds, 4 physical characteristics and 16 of the disinfectants & disinfection by-products. The City-Check Standard testing package allows homeowners to get a more comprehensive analysis on their municipal water supply. This testing package covers everything that is tested for in the City-Check Basic and including more metals, minerals & volatile organic compounds.