The City of Minnetonka has over 260 miles of water mains, 18 deep water wells, 10 storage facilities and 8 water treatment plants. These treatment plants deliver an average of 8 million gallons of water per day to Minnetonka’s residents and businesses.
Minnetonka tap water may sometimes contain small levels iron and manganese that bleed through the city’s treatment system. This level can result in discolored water, staining, and a metallic taste and odor.
Minnetonka water is rated as extremely hard with hardness ranging from 18-20gpg (grains per gallon).
The City of Minnetonka operates 16 wells that draw water from the Prairie Du Chien-Jordan aquifer. The wells range in depth from 405 to 575 feet. The Prairie Du Chien-Jordan formation consists of limestone and granular sandstone that was deposited on the shores of an ancient sea millions of years ago. The water resides in cracks and spaces in the rock. This formation covers much of the Upper Midwest.
The sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and, in some cases, radioactive material, and can pick up substances resulting from the presence of animals or humans. Before a water source is used for a supply, it is tested for contaminants and other water quality parameters.
The EPA has established two standards for additional contaminants in tap water:
MCL: Maximum Contaminant Level – The maximum allowable level of a certain contaminant
MCLG: Maximum Contaminant Level GOAL – The level where studies have found ZERO HEALTH RISKS, aka the “Health Limit”
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.
Water softeners will remove nearly all the calcium and magnesium from the raw water during the softening process. Softeners will also remove up to 10 ppm of iron and manganese. Water supplies with high levels of iron and manganese (greater than 10 ppm) may need pretreatment to prolong the lifespan of a water softener.
Groundwater dissolves rocks and minerals releasing calcium and magnesium ions that cause water to be hard. These dissolved ions give hard water its characteristics.
Water hardness ordinarily is expressed in grains of hardness per gallon (gpg) of water. Water impurities can also be measured in either parts per million (ppm) or milligrams per liter (mg/l). One gpg is equal to 17 ppm (mg/l). Table 1 shows how hardness is classified.
Hard water interferes with all types of cleaning tasks. Cleaning problems arise when the cleaning agents do not fully remove dirt and grime. Over time, clothes washed in hard water may look dingy and feel harsh and scratchy. White clothing continually washed in hard water will gradually show a grayish tinge. Dishes and glassware washed in dishwashers using hard water may be spotted when dry. Hard water causes films on glass shower doors, walls and bathtubs. Hair washed in hard water may feel sticky and look dull.
Regular soaps combine with dissolved calcium and magnesium to form soap curds or soap scum. Soap scum is difficult to remove from sinks and appliances.
Household appliance performance may be affected by hard water use. When heated, calcium carbonate and magnesium carbonate are removed from the water and produce a scale buildup in the hot water heater. A large scale buildup slows the heating process and requires more energy to heat water. Water heaters with large accumulations of mineral buildup will have shorter life spans. Scale deposits also corrode and plug plumbing fixtures and accumulate in other appliances affecting their performance.
• The right water softener will leave your clothes cleaner after washing and will provide you with a bath or shower that you never dreamed could be so refreshing and stimulating.
• A water purification system will turn your tap water into a desirable drink and save you thousands of dollars and untold inconvenience in buying and hauling bottled water home.
• An iron or water filtration system will pay for itself in no time by removing minerals and sediment that shorten the life and efficiency of your water heater and eventually clog and corrode pipes, joints and valves leaving you with horrible problems and costly repairs.
If you live in Minnetonka, and you draw your water primarily from the Prairie du Chien-Jordan aquifer and might be astounded at how “hard” your water is and how much you might benefit from simple forms of water treatment.
The test is inexpensive and will not only provide you with peace of mind concerning your family’s drinking water, but it could very well offer you a higher quality of life in regard to your water use.
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