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1. Why does the City flush hydrants?

Regular flushing improves drinking water quality by removing sediments from inside the mainline and flushing them out through the hydrant. It also serves to identify malfunctions of the hydrant and related valves.

2. When does the City flush hydrants?

The City utility maintenance crews typically flush hydrants throughout the city one time in the spring and again in the fall. Hydrant flushing occurs during construction and water main breaks as well. 

3. Why is my water discolored?

You may notice a color change in your tap water following the flushing of the water main, during construction near your street and following a nearby water main break. The discoloration is normal and will last only a short time after the nearby hydrants have been flushed. When a hydrant is opened, the water in the mainline flows out at a high velocity. This creates a scouring action in the pipe which dislodges fine sediment particles that have accumulated in the pipe. The discoloration is due to suspended particles mixing with water that do not immediately settle.

During construction, frequent opening and closing of the gate valves leads to the same scouring action as during flushing. A significant amount of hydrant flushing occurs during construction and water main breaks, but some sediment usually ends up in water services too. There are no known health hazards associated with the discolored water. 

4. What should I do if my water is discolored?

The discolored water is safe for drinking, but you may choose to reschedule laundry, especially whites, or other work that may be impacted by discoloration. The best way to clear the water is by turning on the cold water in a basement utility tub or an outside spigot for a few minutes. If that doesn’t clear it up, please contact City Hall at 651-204-6000. The hydrants may require additional flushing. 

5. Is the City wasting water when it flushes hydrants?

Flushing hydrants is an important component of a routine maintenance program necessary to maintain the integrity of the water system. This allows the City to continue to deliver high quality water to our customers. It is necessary to periodically flush water through the main lines in order to protect the quality of your drinking water. The volume of water that is released through a fire hydrant quickly flushes off sediment that accumulates on the bottom of the water mains and helps keep the water in the system fresh and clean. This is an important preventative maintenance activity.

6. Why does my water smell like rotten eggs?

Once in a great while, your water may have a “rotten egg” odor. This odor is caused by hydrogen sulfide gas. The odor is unpleasant, but the gas is not usually harmful at the low concentrations that occur in household water systems. For advice on how to get rid of the odor, please contact our City Engineer at 651-204-6050.

7. Why does my water smell like chlorine?

In the fall of 2023 the city transitioned from using chloramines for disinfection to free chlorine.  To do that we had to go through a process called breakpoint chlorination.  You can learn more about that process here watch?v=AH84LOwnh UU.  

Historically, the City of Vadnais Heights had used chloramines for disinfection.  The Minnesota Department of Health notified us that they were concerned with the level of our chloramines and the possibility of forming disinfection byproducts.  To reduce the health risks to our water users we undertook the process of breakpoint chlorination to start disinfecting with free available chlorine (FAC).  Some members of the public will be more sensitive to the presence of FAC.  If a resident is one of those sensitive to the presence of FAC they will notice the change.  Our water is safe and the chlorine levels are sent out of the system near 1ppm, which is considered fairly low by drinking water standards.