Water heater replacement in Los Angeles, installed to current code and strapped

Tank size depends on how many people shower back to back and how quickly the heater recovers. A 40-gallon gas tank works for many two- to three-person households, while families of four or more usually move to a 50-gallon gas tank. Electric tanks recover slower, so they are often sized up by one step.

Look at the first-hour rating on the label, not just the gallons. It tells you how much hot water the heater can deliver in the first hour of heavy use, which matters more on a busy morning than the tank size alone.

If you are open to something different, a tankless unit or a heat pump tank might suit your house better. We compare those options in our guide to tank, tankless and heat pump heaters, and we can install any of them.

Swapping the tank is only part of the job. Codes have changed since many existing heaters went in, and the inspector checks every connection. A new install should leave the heater safe in an earthquake, safe to vent and easy to service.

Many replacements in Los Angeles also need a new expansion tank. When the water service has a pressure regulator or a check valve, heated water has nowhere to expand, and pressure spikes push the relief valve to drip. A small expansion tank on the cold line absorbs that.

• Two seismic straps, upper and lower third
• New gas flex connector, shutoff and sediment trap
• Flue sized, sloped upward and secured
• Relief valve discharge piped to an approved point
• Expansion tank where the system is closed
• Raised platform in garages where required

Some heaters sit in tight closets or attics that are too small for a modern tank. Newer low-emission gas units are taller and wider than the heaters installed decades ago, and the extra insulation adds bulk. Sometimes the doorway has to be widened or the heater moved.

Attic and interior closet installations need a drain pan with a line to the outside so a future leak does not end up on the ceiling below. Closets also need combustion air openings sized for the burner. If your current spot has none of that, we explain the changes and the cost before starting. An undersized gas line can also starve a larger burner, which a gas line correction fixes.

Hard water is the main enemy of a tank heater in Los Angeles. Flushing a few gallons from the drain valve once or twice a year removes loose sediment before it hardens into scale. Checking the anode rod every few years, and replacing it before it is gone, protects the tank lining.

Setting the thermostat around 120 degrees reduces scale buildup and the risk of scalding. If scale is a recurring problem across the house, a whole-house water softener cuts the mineral load reaching the heater, faucets and shower valves.