Water heater sizing Last reviewed June 30, 2026
What Size Water Heater for a 2-Bathroom House?
By the WhatSize editorial team 4 min read Standards-reviewed
A 2-bathroom home usually needs a 50-gallon storage tank (or a tankless rated about 7-8 GPM). Size by how many fixtures run at once, not the number of bathrooms alone, and choose a larger tank if you have an electric heater, which recovers more slowly.
Two Bathrooms Means Planning for Simultaneous Use
The reason a second bathroom changes water heater sizing is the chance of two hot-water draws at the same time, such as a morning shower while the kitchen or laundry runs. The DOE First Hour Rating (FHR) measures how many gallons of hot water a unit can deliver in a busy first hour, and that number, not bathroom count alone, is what you size to.
For most 2-bathroom households of three to four people, a 50-gallon tank covers the morning peak. Electric tanks recover more slowly than gas, so an electric model is a reason to size up rather than down. For tankless, the equivalent is GPM: add up the fixtures that might run together to find the flow rate you need.
Top picks for this size
These Amazon-available picks meet the calculated spec. For region-specific or licensed contractor-installed options, consult a local professional. See our Disclaimers.
2-Bathroom Water Heater Sizing by Household
- 1-2 people, 2 baths: 40-50 gallon tank, or about 6-7 GPM tankless
- 3-4 people, 2 baths: 50 gallon tank, or about 7-8 GPM tankless
- 5+ people or frequent simultaneous showers: 60-80 gallon tank, or 8-10 GPM tankless
- Electric heater: size up one step, since electric recovery is slower than gas
Frequently asked questions
What size water heater do I need for a 2-bathroom house?
Most 2-bathroom homes are well served by a 50-gallon storage tank, or a tankless unit rated around 7-8 GPM. Size up if you frequently run two showers at once, have a large household, or use an electric heater that recovers slowly.
Is a 50-gallon water heater enough for 2 bathrooms?
For a typical three-to-four-person, two-bathroom household, yes. A 50-gallon tank handles the morning peak for most homes. If simultaneous showers are common or the home has five or more people, consider 60-80 gallons.
What GPM tankless do I need for 2 bathrooms?
Add up the fixtures that may run at once. Two showers at about 2 GPM each plus a sink is roughly 5-6 GPM, so a 7-8 GPM tankless gives a safe margin. In cold climates, size up because higher temperature rise lowers a tankless unit's effective GPM.
You might also need
More water heater sizing guides
- What Size Water Heater for a 1-2 Person Household?
- What Size Water Heater for a 3-4 Person Household?
- What Size Water Heater for a Family of 5?
- Tank vs Tankless Water Heater: Which Size Is Right?
- What Size Water Heater for Electric vs Gas Homes?
- Water Heater FHR Chart: First Hour Rating by Household Size
- Tankless Water Heater GPM Chart by Household Size
- Water Heater UEF Rating Explained: Energy Factor vs FHR Chart
- 40 vs 50 Gallon Water Heater: Which Size Do You Need?
Still choosing between sizes? Compare: tank vs tankless