• Shower walls must be made of tile, cement, plastic or another waterproof substance.shower image by Gina Smith from Fotolia.com
  
  Bathroom plumbing can be a relatively complex task, especially for homeowners without professional plumbing experience. Each state has its own building codes and requirements regarding shower and other plumbing installation. Many cities also have their own special requirements. California residents should take the time to learn the rules and regulations for apartment and other residential showers in their areas. Knowing these requirements can make the remodeling and building processes much simpler.
  
  

Size

• According to the 2007 California plumbing code, all shower compartments must have a finished interior of at least 1,024 square inches, and be capable of encompassing a 30-inch circle. The shower must maintain these dimensions to a point 70 inches or more above the drain outlet. The only protrusions that can enter this space are the fixture valves, soap dishes, shower shelves, shower head and safety rails. In disability-accessible shower stalls, fold-down seats may also protrude into the 30-inch circle.
  
  

Disability Access

• Some communities, such as Santa Cruz, also require disability-accessible showers in apartment buildings of three units or more. According to the Santa Cruz Municipal Code, these buildings must have at least one accessible bathroom for each 25 units, at a minimum of one bathroom per building. The code states that an accessible bathroom must include a roll-in shower accessible for wheelchair users. Property owners who buy a building that does not meet these requirements have 30 days to install one after the acceptance of a rental or sales agreement.
  
  

Shower Walls and Doors

• According to the City of Concord, showers in any residential situation in California must have non-absorbent walls up to 70 inches above the drain, and must have doors that open outward, with a minimum clear opening of 22 to inches. Shower doors should have a water dam between 2 and 9 inches tall. According to the City of Novato, shower walls can be backed with cement, fiber-cement, and glass mat when installed over gypsum board.
  
  

Shower Valves

• Control valves in residential showers must be either thermostatic or pressure balance types. A combination thermostatic/pressure balance valve is also acceptable. Older showers with different valve types are acceptable in existing construction, but new showers or remodeled showers must use only these approved types. These valves are required to prevent burns and other problems because of changes in water temperature throughout the building. Elderly people and those with skin sensitivities are at a higher risk for serious injury in showers with unapproved valve types.