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TRUSTED BY O FALLON, MO HOMEOWNERS

  • Average homeowner rating star icon4.4
    Average homeowner rating
  • Verified reviews icon124
    Verified water heater services reviews

Top-Rated Water heater pros in O Fallon - Updated Nov 2026

Avatar for Hosack Plumbing Heating & Cooling
Hosack Plumbing Heating & Cooling
4.8(
345
)
Solar Water Heater System - InstallTankless Water Heater - InstallTankless Water Heater - Install - For Business+6 more

Serving O Fallon, MO and surrounding areas

Approved

In business since 2009

Warranties offered

Credit card accepted

"It started off bad because I had the water heater installed, submitted my paperwork for my rebate for the installation and then my rebate ended up not getting honored because the water heater that was installed didn't qualify for Spire's rebate. Turn's out that the water heater that would fit my location as well as satisfy Spire's rebate, I would have had to wait 5 to 6 weeks for that specific water heater so, the owner of Hosack's Plumbing cut me a check for the amount of the rebate and the amount over time that the new water heater would have saved me. Not the perfect situation but, that was a win win for me as well as Hosack's Plumbing because a good water heater was installed just not one that would quite fit the Spire requirements for the rebate! Hence we didn't need to take a brand new water heater out and replace it with another water heater that was just .05 UEF Higher!"
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+2

Response time8 hrs
8 neighbors recently requested a quote
Recommended by93%of homeowners
Avatar for Dunn Heating Air Conditioning and Plumbing
Dunn Heating Air Conditioning and Plumbing
4.7(
274
)
Water Heater - Install or ReplaceTankless Water Heater - InstallTankless Water Heater - Repair+1 more

Serving O Fallon, MO and surrounding areas

Approved

In business since 2003

Free estimates

Emergency services offered

"This was a complex retrofit tankless water heater installation and out of 30+ companies called and solicited for this project, Brett and Dunn's HVAC was the only company to 1) entertain performing the installation correctly (gas line sizing and calculations), 2) had prior experiencing working with tankless heaters, and 3) took the time to work with me on a long list of specifications. These are bulletproof systems if the installation is done correctly and Dunn/Brett took the time to ensure the install was on point and everything went smoothly. They also installed a softener and filtration system. Everything went well from bid to install and I highly recommend Brett and Dunn's - will use again as I could not be more pleased!"
Additional Photos
Response time2 days
2 neighbors recently requested a quote
Recommended by89%of homeowners
Avatar for Mr. Rooter Plumbing of St. Charles
Mr. Rooter Plumbing of St. Charles
4.9(
7
)
Solar Water Heater System - InstallTankless Water Heater - InstallTankless Water Heater - Install - For Business+6 more

Serving O Fallon, MO and surrounding areas

Approved

In business since 2001

Emergency services offered

Warranties offered

At Mr. Rooter® Plumbing every customer’s individual needs are important. Whether it’s a simple sink clog or a damaged sewer line, you can count on a Mr. Rooter plumber to take care of your plumbing needs – day or night – with never an overtime charge. Our professional service, quality products and honest, up-front pricing make Mr. Rooter the best value in plumbing services nationwide. Mr. Rooter is ready for all emergency plumbing issues, from clogged drains and sewage backups to frozen pipes and leaking water heaters. You can count on an expert diagnosis from Mr. Rooter with our camera inspection tools. Then we’ll fix it right the first time, whether it takes HydroScrub® drain cleaning or trenchless pipe repair, with courteous smiles on our faces. There's a reason they call us Mr.® Call your local Mr. Rooter today.

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+2

1 neighbors recently requested a quote
Recommended by83%of homeowners
Avatar for Brighthouse Plumbing, LLC
Brighthouse Plumbing, LLC
4.9(
9
)
Tankless Water Heater - InstallTankless Water Heater - Install - For BusinessTankless Water Heater - Repair+3 more

Serving O Fallon, MO and surrounding areas

Approved

In business since 2000

Credit card accepted

Offers commercial services

You can expect our technicians to provide timely service, a clear explanation of the work to be performed, and upfront pricing. We focus on providing industry best customer service from start to finish. Our technicians are insured, licensed and bonded.

BrightHouse Plumbing
Water Fountain and Fill Station
Bathtub
Shower
Backflow

+1

Response time10 hrs
Recommended by100%of homeowners
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Water Heaters FAQs, answered by experts

No state requires you to vent an electric water heater. Other installation requirements for water heaters will vary, though, depending on the state and local jurisdiction in which you live. Some places require permits, while others don’t. Some may force you to place the appliance a certain distance from any walls or other appliances, while others don't. When you find a local professional to install a water heater, this expert will ensure you follow all the local regulations.

Yes, a water heater can be replaced in a day and can take between two and three hours to install from start to finish. Even if you encounter extra tasks that need to be completed, the job can still be completed in one day.

You can use multiple tankless water heaters, but that doesn’t mean you should. Adding multiple tankless heaters adds considerable cost to your home in both parts and installation costs. Also, you’re adding many more points of failure in the system, making plumbing issues harder to diagnose. More heaters mean more maintenance, and insurers may want a word regarding the increased risk of water damage. A single, larger unit makes more sense in most situations.

No. Expansion tanks must be installed on the supply side (where heated water flows out) of the boiler. There’s also a list of other requirements for most boilers, including being above the pressure relief valves, being on the inner side of any circulator, and more. Your installation manual should have more information on expansion tank installation requirements and what sort of tank the system is made for.

Going from a tank to a tankless water heater is one of the most effective ways to lower your utility bills. The switch also frees up more space and ensures a consistent hot water supply, as the water is heated on an as-needed basis. It costs between $5,400 and $7,400 to install a new tankless water heater. Most installation companies will also help dispose of your old water tank.

The O Fallon, MO homeowners’ guide to water heater services

From average costs to expert advice, get all the answers you need to get your job done.