When to Flush (and Not Flush) Your Water Heater
A Common Question — But the Right Answer Depends on Your Water Heater’s Age
If you’ve searched online for how often to flush your water heater, you’ve probably seen the same blanket advice: once a year. But at Linek Plumbing Company, our answer is more specific.
If your water heater is new or less than five years old, annual flushing is a smart maintenance step. But if your heater is older and hasn’t been flushed regularly, it may be better not to flush it at all. In fact, flushing an older, sediment-filled tank can sometimes do more harm than good.
Why Older Water Heaters Should Often Be Left Alone
When a water heater hasn’t been flushed in several years, sediment settles and hardens at the bottom of the tank. Once it’s baked in place, trying to remove it can clog the drain valve or even stir up debris that leads to leaks.
We’ve seen it many times in older St. Louis homes—especially in neighborhoods like Ladue, Webster Groves, Maplewood, and Kirkwood—where aging plumbing and hard water combine to accelerate mineral buildup. In those cases, it’s safer to leave the sediment undisturbed and start planning for eventual replacement rather than risk creating a leak or damaging an otherwise functional tank.
When Flushing Is Worth Doing
If your water heater is newer and you’ve kept up with regular maintenance, flushing once a year helps remove mineral buildup and extend the unit’s lifespan. You’ll maintain higher efficiency, quieter operation, and more consistent water temperatures.
However, there’s one big exception: If your home has a water softener system, regular flushing typically isn’t necessary. Water softeners remove calcium and magnesium—the minerals responsible for hard water and sediment buildup—so your tank stays cleaner for much longer. In these homes, a quick annual checkup is usually all that’s needed to make sure everything’s operating properly.
How to Know What’s Right for Your St. Louis Home
Because so many local homes have older plumbing systems and varying water quality, it’s not one-size-fits-all. Here’s a quick guideline from our technicians:
| Water Heater Age | Flushing Recommendation | Why |
|---|---|---|
| 0–5 years old | Flush annually | Prevents buildup from starting |
| 5–8 years old (flushed yearly) | Continue annual flushing | Keeps efficiency high |
| 5+ years old (never flushed) | Don’t flush | Sediment may be hardened and risky to dislodge |
| Any age with water softener | Flushing usually not needed | Minerals are already removed |
| 10–12+ years old | Consider replacement | Efficiency loss and risk of leaks increase |
If your tank falls into the “don’t flush” category, the best next step is to schedule an inspection. Our plumbers can check performance, sediment levels, and safety to help you decide whether to continue using your current heater or plan for a replacement.
The Bottom Line — Maintenance Is Worth It, But Timing Matters
Flushing is valuable preventive maintenance only when it’s done regularly from the start. If it’s been five years or more, a hands-off approach might actually save you a leak and an emergency call.
And if your home has a water softener, you’re already ahead of the game—most soft water systems greatly reduce or eliminate the need for tank flushing altogether.
At Linek Plumbing Company, we’ve maintained and replaced thousands of water heaters in St. Louis’s older homes over the past century. We know when flushing helps—and when it hurts. Contact Linek Plumbing Company to schedule a water heater flush for a unit that is less than 5 years old.
Schedule a Water Heater Flush
If your water heater is under five years old and you want to keep it running efficiently for the long haul, now’s the perfect time for a professional flush.
Schedule your water heater service with Linek Plumbing Company — trusted by St. Louis homeowners for over 100 years.
Request Service
For 24/7 Emergency Service
Call (314) 962-0956
When to Flush a Water Heater:
- 0-5 Years Old
- 5-8 Years Old, previously flushed
When NOT to Flush a Water Heater:
- 5+ Years Old – Previously Never Flushed
- Water Softener system installed
Linek Plumbing Company‘s Preferred Water Softener Brand:
