Home > Education > Contaminants & Risks > Drinking Water Contaminants > Turbidity​​

Quick Facts

• Contaminant Type: Physical
• About: Turbidity (water clarity) is a common indicator for contamination and general water quality
• Treatment Options: Sediment pre-filtration, membrane filtration (E.g., ​reverse osmosis); Turbidity can impact the effectiveness of some treatment types, including chlorination and UV Light

Background
Turbidity is used to measure and describe the clarity (or cloudiness) of water. Cloudy water will have a higher turbidity level, and this measurement is commonly used to evaluate water quality and treatment efficiency. 

Cloudiness is caused by suspended particles in the water, including sediment, sand, algae, organic and inorganic matter, and other microscopic organisms. 

A high turbidity level may indicate the presence of harmful microbial contaminants. Cloudy water can also benefit microbes - floating particles provide shelter by blocking light and disinfectants, while also serving as attachment places for microbes.

Common water quality tests & what they measure:

• Suspended Solids & Turbidity - Water clarity indicator
• Temperature
• pH - A measure of the acidity or alkalinity of the water
• Coliform Bacteria - Indicator for possible contamination with disease-causing microbes
• Nitrogen & Phosphorous - Markers for the presence of nutrients
• Chlorophyll-a - A marker for algal blooms
• Dissolved Oxygen - An indicator of the oxygen available to aquatic organisms

Treatment
Turbidity can be treated with filtration treatments, including membrane filtration (E.g., ​reverse osmosis) and filters targeting sediment. The type of device will depend on the source and area of concern: cloudy drinking water can be treated at the tap, while other entry points, such as showers, will need to be addressed with a whole-house system.

It is important to note that turbidity can impact the effectiveness of chlorine and Ultraviolet (UV) light. 

Resources: 

• USGS: Turbidity and Water [Link]
• USEPA: National Primary Drinking Water Regulations [Link]
• WQA: Cloudiness & Discoloration Issues [Link]