Getting more hot water from a gas tank usually means addressing sediment buildup, checking the thermostat, or reconsidering tank size.
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Quick answer
To get more usable hot water from a gas storage tank, start by flushing sediment that has built up on the tank bottom, since a thick layer reduces effective capacity and slows recovery, then check that the thermostat is set appropriately rather than unusually low. If the tank is simply undersized for the household's actual peak demand, the more lasting fix is either a larger tank or a water heater with a higher recovery rate, since raising the thermostat alone has real limits and safety considerations.
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Before assuming a tank is simply too small, it's worth ruling out sediment buildup, which can genuinely shrink the amount of usable hot water storage over years of operation. A layer of mineral sediment at the bottom of the tank not only insulates water from the burner, slowing recovery, but also physically displaces some of the tank's water volume.
A full flush during service often restores noticeably more usable capacity in an older tank that hasn't been flushed in years, sometimes making the difference between a tank that feels chronically undersized and one that comfortably meets the household's needs.
A tank set to a lower-than-typical temperature will run out of hot water sooner during heavy use, since the usable temperature range between the tank's setting and the point where water feels lukewarm is narrower. Most manufacturers recommend a moderate range that balances comfort, safety, and scale prevention — running it noticeably below that range trades comfort for very little benefit.
It's worth noting that raising the temperature very high isn't the answer either — beyond increasing scald risk, it accelerates mineral scaling inside the tank and can shorten its working life.
| Approach | What it actually does |
|---|---|
| Flushing sediment | Restores lost capacity and improves recovery on an existing tank |
| Adjusting thermostat within safe range | Modest change to usable hot water volume |
| Staggering high-demand activities | Reduces simultaneous peak demand without any equipment change |
| Larger tank or higher recovery rate unit | Addresses genuinely undersized capacity for the household |
A tank's recovery rate — how fast the burner reheats water between draws — matters just as much as raw gallon capacity. Two tanks of the same size can perform very differently during a busy morning depending on burner input, which a technician can factor into a sizing recommendation.
If a household has grown, added a secondary suite, or simply always struggled with the current tank even when it was newer and well maintained, the honest answer may be that the tank was undersized from the start. In that case, a technician can walk through options — a larger tank, a higher-recovery model, or a tankless system — based on actual peak demand rather than guessing at a bigger number.
Safety note
If you ever smell gas near an appliance, the meter, or a vent, leave the home immediately, don't operate switches or a lighter, and call FortisBC's emergency line at 1-800-663-9911 from outside. Gas line, venting, and combustion work on a boiler or water heater should only be performed by a Technical Safety BC licensed gas fitter.
A modest increase within the manufacturer's safe range can help somewhat, but it's a limited fix and pushing beyond that range trades real safety and scale concerns for very little additional usable hot water.
In a tank that's gone years without flushing, sediment can occupy a meaningful portion of the tank's lower volume, which is often more impactful than people expect until it's flushed and the difference is noticeable.
Not always — a higher recovery rate unit of the same size can sometimes solve the problem better than simply going bigger, especially if the issue is speed of reheating rather than raw storage volume.
Yes, a tempering or mixing valve set conservatively can blend in more cold water than necessary at the fixture, making the tank's hot water feel less abundant than it actually is.
A partial drain a couple of times a year with a fuller flush during annual service generally keeps sediment from meaningfully reducing tank capacity over time.
A tankless unit removes the concept of running out, since it heats on demand rather than storing a finite volume, which can be a genuine solution for households that consistently outgrow a tank.
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