As a professional in the plumbing industry, I have encountered many questions about the California Plumbing Code and its requirements for water heater expansion tanks. It is essential to understand these codes and regulations to ensure the safety and functionality of your water heating system. In this article, I will provide a comprehensive overview of the California Plumbing Code (Section 608) and the California Mechanical Code (Section 1005, 0) and their requirements for thermal expansion tanks. The primary purpose of an expansion tank is to alleviate excessive building pressure during the heating process. When water is heated, it expands, causing an increase in pressure inside the tank.
Without an expansion tank, this pressure can lead to pressure spikes and leaks, potentially damaging your water heater. Therefore, it is crucial to follow the California Plumbing Code and install an expansion tank or an equivalent on the list. According to the code, it is recommended to have a water pressure regulator for water heaters with a pressure greater than 80 PSI. This increase in water pressure can occur due to population growth and can cause significant damage to your water heater if left uncorrected. As a professional plumbing company, we offer installation and maintenance services that comply with the California water heater code.
It is also essential to obtain a water heater permit from your local building planning and security office as required by California law. In addition to expansion tanks, the California Plumbing Code also requires that all water heaters be equipped with anti-seismic straps. These straps are crucial in keeping the appliance in place safely during an earthquake. Furthermore, any water system with storage equipment must have an approved, catalogued, and appropriately sized combined temperature and pressure relief valve. The only exception to this rule is for instantaneous non-storage heaters with an inner diameter of no more than 3 inches (80 mm).If you ever need to shut off the water or gas supply to your water heater, whether it be due to a leak, lack of hot water, or maintenance, it is essential to have a shutoff valve that works on both the incoming cold water line and the gas line.
Additionally, it is crucial to have easy access to your water heater in case of any problems. All storage water heaters must also be equipped with a combined temperature and pressure relief valve (T&P valve). This valve will release water if the temperature of your water heater reaches 210 °F or the pressure reaches 150 PSI. If this occurs, it may be a sign that something is seriously wrong with your water heater. It is worth noting that water heaters operating at pressures greater than 150 psi are classified as boilers.
Expansion tanks also help absorb fluctuations in the pressure of incoming water, stabilizing its flow to the water heater. It is crucial to maintain proper water pressure in your plumbing system as very high water pressure can cause damage to pipes, fittings, faucets, and appliances, including water heaters. If your water supply has a backflow prevention device, it is mandatory to install an expansion tank of the appropriate size (see Figure 608.3d), even if you have a T&P valve installed.
