Getting Your Water Tested
Find Your Water Provider
Public water systems provide water to homes and businesses, ranging from a few dozen to thousands of residents. If you live in urban or suburban areas, your drinking water likely comes from a public system and is treated before it reaches your home. Many residents who live outside of urban areas, however, get water from state small water systems or private, domestic wells. Residents who receive water from these sources may not have the resources to treat water to safe standards. Additionally, wells may be located near sources of pollution. To learn where your water comes from, use the QR code to find an interactive map developed by the Community Water Center. [1]
Is My Water Safe?
Large water systems are required to regularly test water to ensure quality. If you live in an area served by a larger water supplier, you can find water quality test results from your provider. Follow the QR code here to see if your water quality complies with water quality standards. [2]
If you live outside of a water system boundary, the best way to know your drinking water quality is to get your water tested by an independent laboratory. You can drop off or mail a sample of your water at the laboratory and have your water tested for common contaminants. Household water quality tests can cost up to $200. Follow the QR code to the right to find a water quality testing lab near you. Many county environmental or health departments have programs for discounted water testing. Check with their county first!
Contaminants
Contaminants in drinking water can affect the taste, odor, and color, and
have human health effects. Drinking water quality standards protect the
public from health impacts caused by contaminants. Common
contaminants include:
Biological
Bacteria, parasites, and viruses (like E.coli and Giardia) originate from many pollutant sources, like water runoff containing manure from animals. Illnesses that can result include intestinal issues, infections, and respiratory problems.
Metal
Metals are naturally present in all waterbodies due to the geology of the local area, but higher concentrations of metals are commonly a result from human-caused pollution. [5]
Chemical
Chemicals as a byproduct of industrial activity like, agriculture or manufacturing, commonly leach into water sources.
Indicators
In addition to directly testing for these contaminants, water quality can be monitored through indicators such as:
pH
pH is a measure of acidity in water. A pH value less than 7.0 is more acidic water, while pH values greater than 7.0 indicate more alkaline, or basic, water. [6]
Turbidity
Turbidity is a measure of water clarity. Water with high turbidity appears cloudy due to small sediment and particles (solids) in the water. [4]
How to Interpret Results
The figure below is an excerpt from the Consumer Confidence Report (CCR) Water Quality Report from the City of Merced [7]. Explore the data below to learn how to interpret water quality test results and understand if your water is safe for drinking.
List of Contaminants
An order of in/organic polluting or poisonous substances that reside in the water. [9]
Primary Drinking Standards
Primary drinking water standards protect public health by limiting the levels of contaminants in drinking water that pose significant health risks. [10]
Secondary Drinking Standards
Secondary standards include contaminants that may affect cosmetic or aesthetic characteristics of drinking water (taste, smell, color) [10]
Maximum Contaminant Levels (MCLs)
MCLs are protective standards established by regulations, which public water systems must meet. An MCL is set based on health risks, detectability, treatability, and costs for treatment for a contaminant. [8]
Public Health Goals (PHGs)
PHGs reflect the level of contaminants in drinking water that pose no significant health risk if consumed for a lifetime. PHGs are established using risk assessment principles and by knowing the costs and health risks associated with contaminants, but are not legally enforceable for public water systems. [8]
Relationship Between MCLs and PHG
A Public Health Goal is first established for a contaminant based on known scientific data, followed by an enforceable Maximum Contaminant Level. MCL requirements are established as close to PHGs as possible, but may surpass PHGs.
