Water in Utah is generally harder than almost every other state, simply based on geography and how water occurs naturally. The State of Utah has a maximum standard for drinking water of 2,000 milligrams per liter (mg/l) for TDS. However, if the TDS level is more than 1,000 mg/l, the water supplier must demonstrate that no better water is available. Three of Herriman’s groundwater (underground) sources have TDS above 1,000, so water from these sources is blended (mixed/diluted) with water from the regional Jordan Valley Water Conservancy District. JVWCD water averages about 250 mg/l of TDS.
Measured in grains per gallon, water is generally considered soft under 4 gpg, moderately hard at 4-7 gpg, hard at 7-10 gpg, and very hard at 10+ gpg. Local Herriman wells are usually between 25-60 gpg, while Jordan Valley Water Conservancy District water is usually 10-12 gpg. So water from Herriman and several surrounding areas is very hard.
You may naturally ask, if Jordan Valley Water Conservancy District water is available to us, why not just use that all the time to reduce the water hardness in our homes?
The drawback of using Jordan Valley Water is that it costs about four times as much as producing from local wells (average of $170 per acre-foot from local sources; $690 per acre-foot from JVWCD). The City has historically used local sources and mixed them with JVWCD water throughout the year, with an additional heavy supply from JVWCD in the warmest months due to higher landscape water usage.
However, due to the extreme hardness and undesirable aesthetic nature (taste, appearance, and even smell) of local water sources, the City Council has decided to exclusively use Jordan Valley water during the off-peak season starting in fall 2024.
