Every situation is different and household hot water needs can change. This all comes down to usage, how many people are using hot water and what are they using it for. If there are four kids in your house that like long hot showers, good luck! The most common water heater we install has a 40 gallon capacity and the water is heated by burning natural gas. There are a lot of options, and we are seeing many customers install a tankless or on-demand water heater (more on that later). This is one of those things that we would discuss when it is time to replace or upgrade to make sure we are putting the right unit in your home or business.