Each year, the city of Minnetonka issues the results of monitoring done on its drinking water from January 1 to December 31 of the previous year. This annual report summarizes drinking water quality for the previous year; advances residents’ understanding of drinking water; and heightens awareness of the need to protect precious water resources.

If you have questions about your drinking water or for information about opportunities for public participation in decisions that may affect the quality of water, contact Jim Malone, utility maintenance manager, at jmalone@eminnetonka.com or 952.988.8400.

Tap water quality reports

Tap water treatment

Although it may not be common knowledge, residents of medium and large American cities enjoy the best drinking water in the world. This is because the water that these people consume is a treated product. Water rarely comes straight from a water source without treatment to improve its quality. Nearly all-large community drinking water systems are treated and Minnetonka is no exception. The following information describes the treatment processes that are used to prepare your water for consumption and household uses.

Treatment procedures


The Minnetonka water supply is chlorinated to remove microscopic organisms in the drinking water. Contrary to popular belief, chlorine rarely impacts the taste of drinking water in a negative manner; in fact, the aesthetic qualities of most drinking water sources are improved by chlorination. One drop of liquid chlorine per gallon of water is normally sufficient to eliminate most disease-causing organisms.


Fluoride is added to Minnetonka’s water at levels mandated by state law, 1.2 ppm. Fluoridated water has been proven to reduce tooth decay, especially in children. Fluoride levels are monitored on a daily basis to ensure proper concentrations.

Iron Removal

Iron is a mineral found in high concentrations in groundwater throughout Minnesota, and Minnetonka’s wells contain significant quantities of this mineral. Although iron is not a threat to human health, water with iron concentrations greater than 0.3 parts per million (ppm) has characteristics that can make it a nuisance to use. Rust-colored sediment may appear in the water and the water may have a bitter, metallic taste. Iron can also leave rust-colored stains on laundry, porcelain, and fixtures. The city of Minnetonka operates 8 iron and manganese removal treatment plants.

Corrosion Control

To mitigate any possible sources of lead or copper contamination originating in home plumbing Minnetonka’s Water Utility adds a corrosion inhibitor to the water. This coats the inside of your plumbing and make piping sources of lead and copper unavailable to corrosion and leaching.

Hydrant flushing

Public Works begins flushing hydrants citywide in March to remove iron and manganese from the system. During this operation you will notice a change in the color of the water, this is normal. If you have questions about the flushing operation call 952.988.8400.


The minerals calcium and magnesium cause water to be “hard.” These minerals are found in ground water throughout Minnesota, and Minnetonka’s water supply wells are typical of the region. The city does not treat the water to reduce hardness levels. But, if hard water is a nuisance to you, you should be aware that Minnetonka’s water hardness is 18-21 grains/gallon (or 280-310 PPM of calcium as CaCO3), a level that responds well to home-softening devices. Be aware that water softeners require maintenance and the regular addition of salt. Softening may increase the sodium level of your water and should be considered for health reasons.

North Dakota State University—Treatment Systems for Household Water Supplies