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A Commerce City Plumber Who Gives You the Price Before He Starts

Jeff Dunlap is a Marine Corps veteran who repairs and replaces water heaters and fixes leaking water lines across the north Denver metro. He walks you through your options first. His customers say the price came in under the other guys.

A new Rheem gas water heater sitting in a drain pan in a utility closet
A Rheem water heater from a recent Mammoth Plumbing job

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The Plumbing Jobs Mammoth Takes On

Water heaters are most of the calls lately. These are the other jobs Mammoth Plumbing handles around Commerce City.

  • Water Heater Repair and Replacement

    Tank or tankless. If yours is leaking or the hot water has quit, you'll hear whether a repair will hold or a new one makes more sense, and what each one costs.

  • Water Line Repair

    A leaking or broken water line repaired, including lines behind a wall that has to be opened up to reach them.

  • Faucets and Sinks

    A drip that won't quit or a tap with no pressure gets fixed. If you want a faucet swapped for a new one, that's covered too.

  • Toilets

    A toilet that keeps running, leaks at the base or needs replacing. One customer had her toilet valve fixed on the same visit as her new water heater.

  • Other Plumbing Repairs

    If something that carries water in your house has stopped working, call and describe it. You'll find out if it's a job for Mammoth Plumbing.

Four white tankless water heaters mounted side by side on a mechanical room wall, with their venting and water lines
Four tankless water heaters on one job
A new copper tee and press fittings joined into a water line inside an opened wall
A copper water line repair behind an opened wall

What Customers Say Happens on a Visit

That's what customers keep bringing up in their reviews, in their own words.

  1. A Heads-Up When He's on the Way

    You get a heads-up when the plumber is on the way, so you can be home and ready.

    “I was informed when he was on his way so I was ready.”

    Michelle, Google review
  2. He Looks at It and Lays Out the Options

    You might be choosing between a repair and a replacement, or between two models. Customers say they hear what each choice means for their home and their budget.

    “Jeff was extremely helpful and honest.”

    Fernando Cardenas, Google review
  3. A Fair Price and a Clear Estimate

    Customers say they got a fair price and a clear estimate before the work. The choice was theirs.

    “didn’t try to upsell me on any unnecessary stuff, and gave me a fair, reasonable price with a clear estimate upfront.”

    Abe Farias, Google review
  4. The Small Stuff on the Same Visit

    Mention the drip or the running toilet during the visit, and ask if it can be looked at too.

    “I asked if he could fix the valve on the toilet after he arrived and he did.”

    Michelle, Google review

Photos From Recent Jobs

These photos are from real Mammoth Plumbing jobs, the same ones on the Google listing.

A new gray Rheem gas water heater on a drain pan in an under-stair storage room, with its flue and expansion tank
A new Rheem tank water heater under the stairs
A white one-piece toilet in a gray bathroom with marble-look floor tile
A one-piece toilet in a finished bathroom
An outside gas meter and gray gas pipe against house siding, with a pressure gauge on the line
A gas line at the meter, with a pressure gauge on it

What Customers Say About Mammoth Plumbing

Word for word from Mammoth's Google listing.

5.038 Google reviews, checked October 2026Read them on Google
  • “I am very satisfied with Mammoth Plumbing. Jeff came to install a new water heater. I was informed when he was on his way so I was ready. He was professional and ready to work. I asked if he could fix the valve on the toilet after he arrived and he did. He saved me a lot of money compared to the other guys. I am going to be using him again to install a new HVAC system when I am ready. I would highly recommend Mammoth Plumbing, Heating and Cooling.”

    MichelleGoogle review, 3 months ago
  • “Our AC was struggling to keep the house cool. We had another company give an estimate. It was outrageous. Mammoth had previously replaced our water heater & I found Jeff's card. I called him and he came and fixed the AC at a great price. Great service!! Highly recommend!!”

    Steve RGoogle review, 3 months ago
  • “Jeff was extremely helpful and honest. Saved me a bunch of money compared to other companies by giving me all the options for a new A/C unit. Had him do some other plumbing work and he did a great job on two separate occasions. Will be using him as long as I live in his service area.”

    Fernando CardenasGoogle review, 3 months ago
  • “Mammoth Plumbing, Heating, and Air Conditioning is awesome. They were prompt and professional, coordinated perfectly with both my tenant and me, and kept us both looped in the whole time. The tech fixed my boiler quickly, didn’t try to upsell me on any unnecessary stuff, and gave me a fair, reasonable price with a clear estimate upfront. I’ll 100% be using them for any future maintenance or repairs. Highly recommend!”

    Abe FariasGoogle review, 4 months ago
  • “I can’t speak highly enough of Jeff. He came out after hours to help with our a/c when everyone else was closed. He is extremely professional and knowledgeable. I plan to use them again in the near future for our plumbing issues. Thanks again MAMMOTH!”

    Michael PorterGoogle review, 3 months ago

Plumbing Around Commerce City and the North Metro

Mammoth Plumbing works in and around Commerce City, including these towns.

Not sure you're in the area? Call and ask before you book.

  • Commerce City
  • Reunion
  • Thornton
  • Brighton
  • Northglenn
  • Westminster
  • North Denver

Frequently Asked Questions

If your question isn't here, call and ask.

Call 720-217-4222
How much does a new water heater cost?

It depends on the size and type of water heater. It also depends on what it takes to hook one up in your home. That's why you get the options and a price on site before any work starts. Call 720-217-4222 to set up a visit.

Can my water heater be fixed or does it need replacing?

Sometimes a part is all it needs. Sometimes the tank is done. The plumber checks it and tells you which, with a price for each option so you can decide.

Do you work on tankless water heaters?

Yes. Mammoth Plumbing works on tank and tankless water heaters. The four tankless units in the photo above are from a recent job.

What areas do you cover?

Commerce City and the north Denver metro. The list above shows the main towns. If yours isn't on it, call and ask.

Tell Us What's Going On

Call and talk it through, or send the form at the top of the page for a call back.

720-217-4222service@mammothtoday.com
Call Now 720-217-4222