After a homeowner shared photos of a do-it-yourself water heater replacement looking for feedback, plumbers flagged a range of potential problems involving the relief valve, venting, shutoffs, and hoses.

Here's what to know

"Replaced water heater and added an expansion tank," the original poster wrote on r/Plumbing. "Looking for any critiques or anything I may have done wrong. Mainly done with press fittings." 

Users focused on the expansion tank placement, the gas shutoff arrangement, and the flexible lines connected to the top of the heater. "Expansion tank should be downstream of water shutoff," one commenter said. "Should have shutoff for gas. Shouldn't use rubber hoses to connect to top of tank."

The temperature and pressure relief setup also came up repeatedly. "Need a discharge pipe on the relief valve," one user wrote.

People also raised concerns about the exhaust setup. More than one commenter said the flue pipe appeared to be missing screws or sitting out of position, and some noted that the old vent hood also could cause safety or performance problems. The OP said in a comment that they replaced the vent hood with a new one.

There was also debate over code-related details such as earthquake straps, vent size, and whether the drain pan material was acceptable. Because those rules differ by location, some of those criticisms may have been moot.

Whether you do it yourself like the OP or have a professional install a new water heater, you could save on energy bills by upgrading to a heat pump model. 

More background

Water heaters combine heat, gas or electricity, pressurized water, and exhaust gases in a single appliance. A missing discharge pipe on the relief valve is not just cosmetic; that valve is designed to safely direct scalding water or steam away from people if pressure rises too high.

On gas-powered units, venting problems can create additional risks beyond the exhaust itself. One commenter warned that stainless steel braided hoses may contain rubber and can fail if hot exhaust spills where it should not, writing: "Under normal circumstances, yea, they'll be fine. But if any conditions prevent your vent from drafting properly and hot air is spilling out of the diverter cap, it can melt those rubber hoses and cause them to rupture."

What can be done?

Anyone replacing a water heater is usually best off starting with local code requirements, following the manufacturer's installation instructions, and making sure the completed work is inspected. If you hire help, ask specifically about the relief valve discharge, venting, gas shutoff location, connector type, and whether the expansion tank is positioned for both code compliance and future service.

For people considering an upgrade instead of a like-for-like replacement, Cala offers smart heat pump water heaters designed to lower operating costs. Its customizable smart heat pump water heaters help homeowners lower their energy bills by heating water only when it's needed. That can be especially useful for families trying to avoid the wasted energy that comes with keeping a full tank hot around the clock.

Heat pump models can cost more upfront, but they often make up for it through lower utility bills, especially when replacing old electric tanks. Smart controls can add another layer of savings by matching heating cycles to household demand rather than heating water unnecessarily.

Whether you stick with a standard replacement or explore a smarter upgrade, it is worth comparing long-term operating costs. Homeowners who want a tailored, efficient setup can also look into how a Cala system might fit their home's water-use patterns.

"All that being said, I've seen worse installs by licensed plumbers," the first commenter said.

Where can I learn more?

These stories dig into other water heater replacement questions.

• A wary homeowner weighed a heat pump upgrade after a plumber's advice raised doubts.

• In Australia, home experts outlined the trade-offs of heat pumps for lower-bill hot water.

• One homeowner highlighted tax breaks and big savings after swapping an old gas heater.

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