Water Softener in Longmont, CO

Does Longmont city water need softening?

Rarely. Longmont Water Utilities draws from North and South St. Vrain Creeks, stored in Ralph Price Reservoir, and from Colorado-Big Thompson Project water that arrives from the Colorado and Fraser rivers by way of Lake Granby, Grand Lake and Carter Lake. It is treated at the Wade Gaddis and Nelson Flanders plants. The city's 2025 report describes the result as soft water, typically 1 to 2 grains per gallon. Most softener makers do not recommend their equipment until hardness is several times that. If a salesperson tells you Longmont water is hard, ask to see a test result from your own tap.

Then why do I see spots or crust?

Soft water can still leave marks. Dishwasher film often comes from detergent dosing or a worn rinse-aid dispenser. Flakes in a faucet screen may be sediment from the water heater or debris shaken loose after work on a main. A rotten-egg smell from hot water usually comes from the heater's anode reacting with the water, not from the supply. Each of those has a fix that costs less than a softener. The city's median home was built in 1991, with about 37% predating 1980, so a water heater nearing the end of its life is a common culprit in older neighborhoods near Main Street.

What treatment does make sense here?

Longmont disinfects with chlorine, and the report lists no violations for 2025. People who dislike the chlorine taste usually get the most from a carbon filter at the kitchen sink or a whole-house carbon unit. The city's service line inventory classified every water service line as non-lead, so filtration choices here tend to be about taste and preference rather than pipe material. Homes on private wells outside city water are a different story and deserve a full water test before any equipment is chosen.

Local note

Longmont Building Services requires a permit for any change to a home's plumbing system, and the Development Services Center on Kimbark Street handles applications. A whole-house filter cut into the main can fall under that rule, so ask the plumber to sort out the permit as part of the job.