Is a shallow sewer line grandfathered in for a remodel in Ca.?

Discussion in 'Plumbing Code Questions' started by Jason Vogt, Jun 30, 2020.

  1. Jason Vogt

    Jason Vogt New Member

    Joined:
    Jun 30, 2020
    Location:
    Ramona, Ca.
    Hello, new to the forum. Have gone through the permitting process and have started demo on a 38' by 34' RV garage in the back yard to convert to an ADU with a kitchen and relocated bath room, built and permitted with the house in 1983. Had the plumber come out yesterday for the new plumbing for a kitchen sink and bathroom vanity. Discovered that the sewer line running through the center of the building is only 1" inch or so beneath the cement slab in the back of the building, and about 14" below in the front (They installed clean outs on both sides). The plumber mentioned that the current code is 18" and deeper, and that he wanted to consult with some of his colleagues. My question is, will this existing shallow sewer line be grandfathered in, or should I plan to start tearing up some cement. The whole back yard is concrete the whole length of the line.

    Thanks for your answers and any advice is welcomed.

    Jason
     
  2. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    I know nothing about CA codes and a call to your building inspector may be needed for an answer. Generally with remodeling anything that is touched needs to be brought up to code. The reason for the 18" depth may have to be for impact protection such as if it ran under a dirt driveway. Under concrete it is well protected. Another could be for CA seismic codes. A problem could be slope. Starting at 18" at the beginning may get too deep at the sewer connection. Hopefully someone from CA can provide advice.
     
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  4. wwhitney

    wwhitney Active Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    Some relevant excerpts from the 2016 California Plumbing Code, based on the UPC. I think there's one newer version in force, and while I doubt they have changed, it bears checking:

    Definitions:

    Building Drain. That part of the lowest piping of a drainage system that receives the discharge from soil, waste, and other drainage pipes inside the walls of the building and conveys it to the building sewer beginning 2 feet (610 mm) outside the building wall.

    Building Sewer. That part of the horizontal piping of a drainage system that extends from the end of the building drain and that receives the discharge of the building drain and conveys it to a public sewer, private sewer, private sewage disposal system, or other point of disposal.

    Chapter 7 Part II covers Building Sewers. Section 718.3 has something to say about depth:

    718.3 Protection from Damage. No building sewer or other drainage piping or part thereof, which is constructed of materials other than those approved for use under or within a building, shall be installed under or within 2 feet (610 mm) of a building or structure, or part thereof, nor less
    than 1 foot (305 mm) below the surface of the ground. The provisions of this subsection include structures such as porches and steps, whether covered or uncovered; breezeways; roofed porte cocheres; roofed patios ; carports; covered walks; covered driveways; and similar structures or appurtenances.

    So if you're using a drain pipe suitable for use under or within a building, I see no burial depth requirement. If the drain pipe material changes to something not suitable for use under or within a building, it needs to be at least 2' away from the building and at least 1' under the ground.

    That's all a cursory check found, it's possible I missed some other relevant section.

    Cheers, Wayne
     
  5. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    If the original slab was installed & plumbing for this RV garage and was permitted and signed off, you may be OK, you're changing everything else. If no permits were issued, then that could be a problem.
     
  6. Jason Vogt

    Jason Vogt New Member

    Joined:
    Jun 30, 2020
    Location:
    Ramona, Ca.

    Thank you.
     
  7. Jason Vogt

    Jason Vogt New Member

    Joined:
    Jun 30, 2020
    Location:
    Ramona, Ca.
    I did some checking with the City before starting, and they did find that the building was constructed and permitted when the original house was built. But they had no further details than that. I have no idea if that original permit included the original toilet and vanity that was here when I bought the place 3 years ago. But the sewage line is under the slab and i don't see any signs that it was installed after the slab was poured.

    I have a plumber asking his colleagues for some advice, if that comes up empty I'll call the city and try to get some advice there.
     
  8. Jason Vogt

    Jason Vogt New Member

    Joined:
    Jun 30, 2020
    Location:
    Ramona, Ca.
    Thank You
     
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