Water Heater Sizing & Recirculating Pumps
Two very different complaints land on our schedule constantly, and they usually trace back to the same root issue: a water heater that doesn't match how the household actually uses hot water. One is running out of hot water mid-shower. The other is standing at the sink for what feels like forever waiting for hot water to show up. Both are usually fixable — and both usually come down to sizing, not a failing unit.
The "Running Out of Hot Water" Problem
If your water heater can't keep up with back-to-back showers, a full load of laundry plus a dishwasher cycle, or a houseful of guests, the issue is often capacity, not a malfunction.
Tank water heaters are rated by how many gallons they hold and how quickly they can reheat that water (the recovery rate). A unit that was correctly sized for a smaller household — say, a two-bedroom home with two occupants — will struggle in a home that's since grown to four or five people, or where usage patterns have simply changed over time.
Rule of thumb for tank sizing:
1–2 people: 30–40 gallon tank
2–3 people: 40–50 gallon tank
3–5 people: 50–65 gallon tank
5+ people or homes with soaking tubs/multiple bathrooms used simultaneously: 65+ gallons or a tankless system sized for higher flow
These are general guidelines — actual sizing also depends on your specific fixtures, how many bathrooms run hot water at once, and your household's peak-use habits, like back-to-back morning showers before work and school.
The "Waiting Forever for Hot Water" Problem
This one is a different issue entirely, and it's extremely common in larger homes or homes where the water heater is located far from the bathrooms or kitchen — which describes a lot of newer construction throughout Queen Creek, San Tan Valley, and Gold Canyon, where larger floor plans are the norm.
When a fixture is far from the water heater, the hot water sitting in that long run of pipe cools down between uses. Every time you turn on the tap, you're waiting for that cooled water to clear the line before hot water actually arrives — sometimes 30 seconds, sometimes well over a minute.
This isn't a sizing problem in the traditional sense. The water heater itself may be working perfectly. The issue is distance and pipe layout, and the fix is different:
A recirculating pump continuously or intermittently circulates hot water through the home's pipes (typically on a timer or a demand-activated switch), so hot water is already present in the line by the time you turn on the faucet, instead of you waiting for it to travel the full distance from the water heater.
Recirculating systems can be installed as a dedicated return line (most effective, but requires more plumbing work) or as a retrofit system using the cold water line as the return path (less invasive, slightly less efficient, but a practical option in homes where running new piping isn't feasible).
Why This Matters More in Larger Arizona Homes
A lot of homes built across the East Valley in the last 15-20 years have larger footprints, primary suites on the opposite side of the home from the water heater, and multiple bathrooms running at different distances from the unit. That layout creates exactly the conditions where a recirculating pump makes a noticeable difference — particularly for larger homes throughout Gilbert, Queen Creek, and San Tan Valley, where we see this combination most often.
Hard water also plays a role here, even though it's a separate issue. Mineral scale buildup inside a tank reduces effective capacity over time and slows recovery, so a tank that was sized correctly when it was new may genuinely be underperforming today if it hasn't had any maintenance.
How to Know Which Problem You Have
A simple way to think about it:
If hot water runs out during normal use, but arrives quickly when you turn on the tap, your issue is likely capacity — and a properly sized tank (or a tankless system) is the fix.
If hot water takes a long time to arrive, but doesn't run out once it does, your issue is distance and pipe layout — and a recirculating pump is the fix.
If both are happening, it's worth having both evaluated together, since the right size and the right delivery setup work as a pair.
We'll Size It Based on Your Actual Home
When we evaluate a water heater, we don't just look at the number on the old unit and replace it with the same size. We look at your household size, your fixture count, your usage patterns, and your home's layout to recommend a setup — tank size, tankless, or a recirculating addition — that actually matches how your home uses hot water.
Mountain Vista Plumbing serves Mesa, Gilbert, Chandler, Apache Junction, Queen Creek, San Tan Valley, Gold Canyon, and the surrounding Phoenix Valley. Call (480) 847-9769 or request a free estimate, and we'll help you figure out exactly what your home needs.
