Wastewater guidelines are available: these guidelines are based on internationally recognized standard water and wastewater testing methodologies as well as government recognized testing requirements in the European Union, the United States of America....For details consult https://www.roadmaptozeo.com --pdf
In drinking water, TDS is measured as ppm or mgl-1. The TDS does not present a risk to human health, the USEPA has not set a mandatory TDS limit, but suggests a maximum level of 500 mgl-1. The permissible limit of chloride (250 mgl-1), Calcium (200 mgl-1), Magnesium (150 mgl-1), the permissible limit of fluoride (1- 1.5 mgl-1) in most of the groundwater samples, and sulphate permissible limit (200 mgl-1) given by WHO and EPA . The values of the chemical content in all water samples are lower than the permissible limit by WHO.
Go through the file attached below providing the details about the permissible limits of heavy metals in Primary drinking water, Hazardous waste screening criteria, Surface water quality, Land application of sewage sludge and much more.