Plumbing jobs are typically not do-it-yourself projects. Fixing the broken chain on the lever in your toilet tank is one thing, but replacing old piping is another matter. Although most minor plumbing work does not require a licensed contractor or a permit from the Department of Building Inspection (DBI), be honest with yourself about which repairs you are willing and are capable of tackling. Also keep in mind that improperly installed plumbing could cause significant damage to your home. Hiring a professional might be well worth the investment, even when not legally required.

• When must you hire a licensed professional and/or obtain a permit?

Any job that involves cutting into or removing piping calls for a permit — and any work that requires a permit must be performed by a California Licensed Contractor. However, if you can prove to a DBI inspector that you have sufficient knowledge of plumbing, you may be approved to do the work yourself. If interested, ask about this waiver at the time you file for your permit. You should also be aware that the designation “plumbing” covers installation of water systems, drainage and waste piping systems, gas piping systems, and vents from gas-fired appliances, water heaters and furnaces — not just water and sewer piping.

• Where can you get an application and how long does it take to get a permit?

You can obtain an “Application/Permit to Install Plumbing, Gas, Water, and Mechanical” from the DBI, 1660 Mission Street, First Floor. Plumbing inspectors are on hand to answer your questions and make sure that you are completing the correct permit applications. Note that you must obtain a separate permit for each type of piping included in the proposed work — water, sewer, etc. Fees are based on the number of permits and site visits required and the DBI will issue your permit over the counter. (Licensed contractors may submit certain permit applications through the Department of Building Inspection Web site after they have registered for this service.)