Frequently Asked Questions

How do you make sure my water is safe to drink?

Madison Water Utility’s testing team conducts more than a thousand tests every month to continuously monitor quality and safety. Our water more than meets strict Federal and State drinking water standards and complies with the Safe Drinking Water Act .

• Latest Annual Drinking Water Quality Report
• Find out the water quality for wells serving your address

For more information, call our Water Quality Department at (608) 266-4654.

What do I do if my water is discolored?

Water from Madison's aquifer often contains low levels of naturally occurring iron and manganese, which can accumulate as sediment in water mains. The minerals aren’t considered harmful, but their accumulation over time can cause water to have a slight brown or reddish tint. We regularly flush our water mains in the spring and summer months to push out the sediment, but that action -- or any other disturbance such as fire suppression, a main break, contractor work, or a flow test -- can temporarily stir up the sediment that causes discolored water. If your water becomes discolored, run a cold water tap in the basement at full force until the water clears. Usually it clears in just a few minutes. If it doesn’t, call the utility Water Quality hotline at (608) 266-4654.

What is Madison's "water hardness" and how does it affect me?

Madison's tap water is considered to be “very hard,” because of the minerals such as calcium and magnesium in the rock formations from which we draw water. This water contains 18-20 grains of hardness per gallon. There are no harmful health effects associated with these minerals (in fact, some believe they are beneficial), but measuring them does provide a guideline as to how water use may be affected. For example, hard water does result in more scale buildup and you need to use more soap and detergents. If you choose a water softener, it's recommended that a separate, unsoftened supply of water be kept for cooking and drinking.  Ion exchange water softeners remove hardness by replacing the calcium and magnesium with sodium salt.

Also, when you buy a new appliance, such as a dishwasher, the manufacturer often makes reference to water hardness. This is because hard water can cause automatic dishwashers to leave film on dishes and build-up of minerals on mechanical parts. It may also cause washing machines to leave residue on articles of clothing and scales that clog water pipes or foul appliances such as water heaters.

Why does my water smell like chlorine?

A small amount of chlorine (generally about 0.3 milligrams per liter) is added at each wellhead to kill any viruses or bacteria that could be present in groundwater. This harmless amount of chlorine helps keep the water protected all the way to your tap. We add chlorine as a gas, which does allow it to dissipate out of the water.  If you are bothered by a slight chlorine smell or taste, you can fill a clean pitcher with cold water, leave the container at least partially exposed to air, and let the water sit.  Most, if not all, of the chlorine will dissipate within 12 hours.  The container can be left on the counter or in the fridge -- the key is to not completely seal the container.

Why do we add flouride to Madison's water?

We began adding fluoride to Madison's water in 1948 at the direction of the Common Council. The move was part of a city policy to reduce the risk of dental cavities, particularly for children with little access to routine dental care. Madison Water Utility follows the recommendation of the Public Health Madison Dane County (PHMDC) with regard to fluoride levels added to drinking water. In 2014, PHMDC issued an updated policy statement on Fluoridation of Public Drinking Water.

What is wrong if I smell a rotten egg odor when I run water in the house?

The smell of rotten eggs indicates the presence of hydrogen sulfide.  The odor originates as sewer gas being displaced from the drain when the tap is run.  A simple test is to fill a glass of water, take it to a room that has no water, and then sniff the water.  If the water no longer has an odor, the drain is the source.  A remedy for cleaning the drain is to pour one-quarter cup baking soda down the drain and follow it with a cup of vinegar.  When the fizzing stops, flush the drain with boiling water. If your tap water has an unusual taste or odor, call the Water Utility at (608) 266-4654.

What is the white residue on pots and pans after I boil water?

Madison tap water is very “hard.” Groundwater sources contain significant amounts of calcium and magnesium hardness, and Madison is no exception.  The minerals in the water leave a conspicuous white residue or spots when water is boiled or evaporates.  This residue is primarily calcium and is not harmful to human health.  Even if you have a water softener, in most homes the kitchen cold water tap is plumbed to receive unsoftened water that still has calcium and magnesium.

Does Madison use chloramine?

No, Madison Water Utility does not use chloramine in our drinking water. We disinfect the water with pure chlorine gas. If you wish to remove chlorine from your tap water, leave an open container of water in the fridge overnight. This will give the gas time to escape.

Why does drinking water often look cloudy when first taken from a faucet and then clear up?

The cloudy water is caused by tiny air bubbles in the water similar to the gas bubbles in carbonated soft drinks. After a while, the bubbles rise to the top and are gone. This type of cloudiness occurs more often in the winter, when the drinking water is cold.

If I am on a salt-restricted diet, will the sodium in drinking water hurt me?

The short answer is no.  For an individual on a restrictive sodium diet who consumed two liters of water daily, the City of Madison’s drinking water would account for no more than 4.7 to 14.1% of the allotted sodium budget, dependent upon the severity of the restriction (1,500 to 500 mg per day).  For more detailed information, click here.