FAQ ยท Thornton, Colorado
Plumbing FAQ for Denver Metro homeowners
Short answers to the questions we hear most about Underhill Plumbing Services, water heaters, fixtures and leaks. If yours isn't here, call (303) 472-4368.
About Underhill Plumbing Services
What does Underhill Plumbing Services do?
Residential plumbing: water heater repair and replacement, tankless water heaters, faucets, toilets and fixtures, leak and pipe repair, gas line repair and whole-home water filtration, plus 24-hour emergency plumbing for burst pipes, active leaks and water heater failures.
Where do you work?
The Denver Metro area, from our base in Thornton: south to Castle Rock and north to Longmont, including Northglenn, Westminster, Arvada, Lakewood, Denver, Aurora and Centennial. Enter your ZIP code when you book to check. See the service area page.
Do you work in condos and townhomes?
Yes. Houses, townhomes and condos. In a condo, check whether your HOA controls the main water shutoff before work that needs the water off.
Do you do commercial plumbing?
We focus on homes. Light commercial work, like a small office or shop, is considered case by case. Call (303) 472-4368 to ask.
Is Underhill Plumbing Services licensed?
The company is owned by John Kuykendall, who holds Colorado Master Plumber License #03002471. See our licensing page.
What are your hours?
7 AM to 9 PM, every day, with 24-hour emergency service for burst pipes, active leaks and water heater failures.
Can I book online?
Yes. Online scheduling lets you pick a requested arrival window; we confirm by text or call.
Water heaters
Is no hot water an emergency?
Usually not, unless the tank is leaking. Book a visit or call. See no hot water.
How long does a water heater last?
The U.S. Department of Energy puts typical tank life at 10 to 15 years and says most tankless units last more than 20. See signs it's time to replace.
Should I get a tank or tankless water heater?
It depends on your household, your gas supply and how long you plan to stay. We compare them in tank vs. tankless in Colorado homes.
What is Colorado's new water heater NOx rule?
Under HB23-1161, most new natural-gas water heaters sold in Colorado since January 1, 2026 must meet low-NOx emission limits. It affects replacement models, not repairs.
Fixtures and leaks
Why does my toilet keep running?
Usually a worn flapper, a fill valve that won't shut off, or a float set too high. See toilet repair.
Where is my main water shutoff?
Usually where the water line enters the house: a basement wall facing the street, a utility room, a crawl space or the garage. Find it before you need it.
How do I keep pipes from freezing?
Keep the heat on, disconnect hoses before the first hard freeze, and open cabinet doors on exterior walls during cold snaps. More on burst pipes.
Pricing and offers
How much will my repair cost?
We price the job once we've seen it, because the same problem can take very different work in different homes. Each service page lists what affects the cost.
Do you have any specials?
See our special offers. Mention the offer when you book.
Still have a question?
Call and ask. It's usually faster than reading.