An old water heater might seem like the perfect candidate for overdue maintenance, but commenters in a Reddit thread warned that a first flush this late can easily backfire.

Here's what to know

According to a post on Reddit's r/askaplumber, the homeowner has an electric 80-gallon Bradford White that is nearly 18 years old and still working with no current problems. Aside from what they believed was a thermostat replacement about six years earlier, they reported no repair history. They also said they had never flushed the tank and did not know whether the anode rod had ever been replaced.

The original poster asked, "What do the experts suggest in this situation? I realize I'm living on borrowed time already with the age of the unit."

The replies mostly pointed in the same direction: leave the unit alone and start a maintenance routine with the next one instead. One commenter wrote, "You havent done anything in 18 years, dont start now. You are just asking for trouble." 

Another said, "Although you will probably need a new one soon, once you get the new one you can start your yearly maintenance."

When a replacement is necessary, homeowners can save on energy bills by upgrading to a heat pump water heater. 

More background

The advice to leave the unit alone may sound counterintuitive, since flushing is generally considered standard upkeep for tank water heaters. When it's done regularly from the start, it can help reduce sediment buildup, preserve capacity, and keep the unit operating more efficiently, especially in homes with hard water.

But in this case, the main issue is timing. In a tank that has gone nearly two decades without being flushed, sediment may already be heavily packed at the bottom. Trying to stir it up and force it out through an older drain can clog the valve, expose weak spots, or trigger leaks that were not obvious before.

Several replies focused less on cleaning the tank and more on what happens if it fails. Because this heater is in a garage, a leak may be less likely to cause major indoor damage, but it could still leave the home without hot water.

What can be done?

With a tank this old, the more practical advice was to plan for replacement rather than test your luck with first-time maintenance. That can include adding a leak sensor, turning off the unit and supply valve before long trips, and budgeting ahead so a breakdown doesn't turn into an expensive emergency.

People in the thread also discussed ways to set up the replacement unit more effectively. Suggestions included adding a full-port ball valve on the drain to simplify future maintenance and swapping a magnesium anode for a powered version.

For homeowners considering a modern replacement, Cala is one option worth considering. The company makes customizable smart heat pump water heaters that help homeowners decrease their energy bills by heating water exactly when it's needed. 

Instead of running on a one-size-fits-all pattern, the system is designed around individual household usage, which can help cut wasted energy. For larger families or homes with heavy hot water demand, that could mean a steadier supply and lower monthly costs from a unit like Cala.

As one commenter put it, "Be one step ahead of the failure. It's coming. You know that! You've got your money's worth out of it. Replace it now before it fails on the wrong day! Be proactive instead of reactive."

Where can I learn more?

If this sounds familiar, these stories dig into the kinds of issues homeowners run into as water heaters age. They cover warning signs, maintenance choices, and replacement decisions.

• Plumbers joked that this outdated water heater looked ancient before warning it could fail.

• A home expert shared tips to keep your water heater efficient and save money.

• One corroded 10-year-old gas unit left a homeowner ready to replace it and weighing tankless options.

Get TCD's free newsletters for easy tips, smart advice, and a chance to earn $5,000 toward home upgrades. To see more stories like this one, change your Google preferences here.