What can cause our water to have an earthy odor or to smell like rotten eggs?

Naturally-occurring organic compounds are created when plant material decays in lakes and reservoirs. Those organic compounds frequently cause musty, earthy odors, especially toward the end of summer. The odors can be objectionable, but generally are not harmful to health. However, odors can be caused by other constituents as well, so you might want to call your local Health Department and mention the odor to them.  

In some parts of the country, drinking water can contain hydrogen sulfide gas, which smells like rotten eggs. This can occur when water comes into contact with organic matter or with certain minerals, such as pyrite. This situation mostly occurs as groundwater filters through organic material or rocks.

The best way to find out what is in your water is to have the water tested by a state certified laboratory. A list of these labs is available from your State Certification Officer.

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Why is our porcelain sink stained brown?

The brown stain is from a large amount of iron in your water. It is closely related to simple rust that you see on metal, which is iron oxide. Your water probably comes from groundwater that filtered through rocks containing iron-rich minerals on its way to the well.

Why does my drinking water look cloudy sometimes?

Once in a while you get a glass of water that looks cloudy; maybe milky is a better term. After a few seconds, it miraculously clears up! The cloudiness is due to tiny air bubbles in the water. Like any bubbles, the air rises to the top of the water and goes into the air, clearing up the water. The water in the pipes coming into your house might...

Where can I find information about my local drinking water supply?

The best way to learn about your local drinking water quality is to read the annual drinking water quality report/consumer confidence report that water suppliers now send out by July 1 of each year. The reports are often sent out with water bills, but they may be sent separately. The reports tell where drinking water comes from, what contaminants...

What can be causing our drinking water to have a reddish color?

Your water might be affected by iron, which is a commonly-occurring constituent of drinking water. Iron tends to add a rusty, reddish-brown (or sometimes yellow) color to water. If the color is more black than red, your water might contain a combination of iron and manganese. Both of these metals can cause staining of plumbing fixtures or laundry...
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Photo of a young girl drinking water, which likely originated from groundwater sources. 
January 17, 2017

A young girl drinks water, which likely originated from groundwater

A young girl drinks water, which likely originated from groundwater sources. 

The USGS is near the midpoint of a complex undertaking to survey the quality of the nation’s largest drinking-water resource. From 2012 – 2023, the USGS is assessing groundwater throughout the country through extensive sampling. The latest results from five regional aquifers are now

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Drinking water from tap
December 31, 2016

Drinking water from tap

The quality of the water we drink can potentially impact our health. The USGS has several programs and cooperative projects that characterize the quality of selected rivers and aquifers used as sources of drinking water to community water systems in the United States.

Attribution: Water Resources
Leaf litter
November 17, 2016

Leaf litter

The timely removal of leaf litter can reduce harmful phosphorus concentrations in stormwater by over 80 percent in Madison, Wisconsin.

September 1, 2016

Drought, Drinking Water and Natural Environments

This short video is one of a series of four total shorts highlighting USGS water science in California's Delta region. The Sacramento-San Joaquin Delta is the hub of the state's water system. Water quality touches on all aspects of life. Teams of U.S. Geological Survey scientists along with their partners monitor water quality and identify sources of pollution and

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Image: Leaf Me Alone!
May 28, 2014

Leaf Me Alone!

In this photo, Joseph Whittier, a student with the Maine Office of the New England Water Science Center, takes a break from scooping leaves to pose for a photo. 

These pools are part of a research effort in the Bear Brook Watershed, in cooperation with The University of Maine. The USGS gages a very small drainage in the watershed, using these two pools. The first

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Two USGS National Research Program scientists taking water samples in a wetland.
January 4, 2006

NRP-02e-biogeochemical-organic-contaminants.jpg

Two USGS National Research Program scientists from the Biogeochemical Controls on Contaminant Degradation in Heterogeneous Near Surface Environments project taking water samples in a wetland.

Attribution: