Tankless Water Heater in Longmont, CO

How soft is Longmont water, and what does that mean for a tankless unit?

Very soft. The City's latest water quality report says Longmont water typically runs 1 to 2 grains per gallon, roughly 19 to 25 ppm of total hardness. It comes from North and South St. Vrain Creeks, stored in Ralph Price Reservoir, plus Colorado-Big Thompson water from Carter Lake, treated at the Wade Gaddis and Nelson Flanders plants and disinfected with chlorine. With water that soft, minerals settle in a tankless heat exchanger slowly, so the manufacturer's standard flush schedule is usually plenty and a softener isn't needed to protect the heater. You should still flush on schedule, since warranties often require it and sediment can collect in inlet screens over time.

Does a Longmont house need changes for tankless?

Often only modest ones. Census survey figures put Longmont's median build year at 1991, with about 37% of homes built before 1980. Many newer houses have a garage or basement wall close to the heater, which makes a sealed vent easy. Older homes near downtown Main Street are more likely to share a chimney between the furnace and water heater, and a gas tankless unit can't use it. In either case the gas line matters: a tankless burner can draw several times what a tank does at full fire, so the pipe from the Xcel Energy meter is measured against the furnace, range and other gas appliances. Because Longmont sits about a mile above sea level, the plumber also applies the maker's altitude derating when choosing a size.

What permits and inspections apply?

Longmont requires a permit for any change to electrical, gas, mechanical or plumbing systems, and water heaters are listed specifically. Building Services is at the Development Services Center, 385 Kimbark Street, (303) 651-8332. The installing plumber usually files the permit and schedules the inspection, which looks at gas piping, venting and the relief valve. For questions about the water itself, Longmont Water Utilities is at (303) 651-8416 on weekdays.

A local note

If you smell gas around the heater, leave the house first. Once you're outside, call 911 and Xcel Energy at 1-800-895-2999.