Tankless Water Heater in Boulder, CO

Signs a tankless unit makes sense

• Your tank heater is near the end of its life, with rust, rumbling or seepage at the base
• Back-to-back showers leave the last person with lukewarm water
• You'd like to free up a closet or basement corner
• An existing tankless unit flashes codes or won't hold temperature
• You're already replacing the furnace and want to rethink the shared flue

Boulder specifics

City of Boulder Utilities treats water at the Betasso and 63rd Street plants from sources that shift by season, including Barker Reservoir, North Boulder Creek, Carter Lake and Boulder Reservoir. It disinfects with chlorine rather than chloramine and runs a corrosion control program to reduce lead from home plumbing. The annual report doesn't give a hardness number, so set the descaling schedule from the manufacturer's guidance or a home water test.

Boulder's housing ranges widely, from older bungalows near downtown and the University of Colorado campus to newer homes on the edges. The city encourages owners of pre-1956 homes to check their service line material on its online map, and those older houses are also the ones where the water heater often vents through a masonry chimney shared with the furnace. A gas tankless unit needs its own sealed vent, so the plumber looks for an exterior wall close to the heater location. Condensing units also need a drain for condensate.

Xcel Energy supplies gas. If you smell it, leave the house, then call 911 and Xcel Energy at 1-800-895-2999.

What affects cost

• Gas supply. Tankless burners pull a lot of gas at full fire; the line from the meter may need a larger size.
• Vent route. Short sidewall exits cost less than runs through finished ceilings.
• Electrical. Gas units need an outlet; electric tankless units need major panel capacity.
• Location. Moving the heater from a crawl space or basement corner adds piping.
• Permit. Boulder classifies water heaters as a single-trade permit.

What happens when you call

The call connects you with an independent plumber who works in Boulder. Have the heater's age, fuel type and number of bathrooms handy. The plumber usually pulls the single-trade permit through Planning & Development Services (1101 Arapahoe Ave, 303-441-1880) and schedules the inspection. If you ever need the city to shut off water after hours, Boulder asks residents to call 303-441-3200.