In the Field · Part 4
Sewer and drain II: trenchless vs. open trench, whose lateral it is (it varies by city), backwater valves, and point-of-sale lateral ordinances
When the camera shows a lateral that has to be replaced, the plumber has three questions before a price: how (open trench, pipe bursting, or a cured-in-place liner), whose pipe it is (in some California cities the owner is responsible all the way to the main, including under the street; in others the city owns the lower lateral from the property line), and what the city requires at the connection (an encroachment permit, a backwater valve, a cleanout at the property line). This lesson answers each with the method, gives the backwater valve rule that protects a low fixture and the customer's insurance claim, and explains the East Bay's point-of-sale lateral program as the model for the ordinances a plumber has to know before quoting a sewer job near a sale.
What the full lesson covers
- Open trench replaces the line and lets you fix the grade; pipe bursting replaces it through the old path with one pit at each end and cannot fix a belly; a cured-in-place liner rehabilitates the existing pipe from the inside and depends on the host pipe's shape. Match the method to what the camera and locator showed.
- Whose lateral: in unincorporated Los Angeles County the owner maintains the entire lateral to the main, including under the street (LACC 20.24.080); some cities own the lower lateral from the property line; every job starts with the city's ordinance and, for the street portion, an encroachment permit.
- A fixture on a floor lower than the next upstream manhole cover must be protected by a backwater valve, and fixtures above that level must not discharge through it (CPC 710.1). The basement bathroom and the sunken laundry are the candidates; the valve is a permitted job.
- Point-of-sale ordinances: in the East Bay PSL program area, a Certificate of Compliance is required at transfer of title, at a remodel of $100,000 or more, or at a meter size change, before escrow can close. Other cities have their own; a sewer job near a sale is quoted against the program's test, not just the camera.
- Every lateral job: one-call notice before digging, the trenching rules, the permit, the inspection before backfill, and a video before and after.
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More lessons in The Field: Method, Code, and Cases
- 1The diagnostic method: verify, isolate, cheapest test first, cause not symptom, the options ladder, document
- 2Permits: when one is required, what is exempt, pulling it online, the inspection sequence, what inspectors look for, and handling corrections
- 3Daily-use code: drainage slope, venting, water sizing, cleanouts, trap arms, and fixture units, with the section for each
- 4Gas piping in practice: sizing, CSST bonding, the pressure test, appliance connectors and shutoffs, sediment traps, and seismic shutoff valves
- 5Water heaters I: tank. Seismic strapping, the T&P discharge line, expansion tanks, sediment traps, pans, venting, and the garage rules
- 6Water heaters II: tankless and heat pump. Gas sizing, venting, condensate, the 2025 Energy Code direction, and where the gas-ban ordinances stand
- 7Sewer and drain I: the camera, the locator, hydro-jetting vs. cabling, and when each is the right tool
- 8Sewer and drain II: trenchless vs. open trench, whose lateral it is (it varies by city), backwater valves, and point-of-sale lateral ordinancesYou are here
- 9Case: the hissing line. The meter test, the supply leak that fed the roots, the lateral to the city tap, and the contract and permit trail
- 10Leak detection: slab leaks, acoustic and pressure methods, thermal imaging, and repipe vs. reroute
- 11Low pressure: the PRV, galvanized pipe, and the sequence that finds which one it is
- 12Sewer gas: trap seals, trap primers, vents, and the sequence that finds the smell
- 13Water treatment: where softeners are restricted in California, filtration, pressure regulators, and thermal expansion
- 14Fixtures and conservation: CALGreen flow rates, SB 407 retrofit-on-alteration and disclosure-on-sale, 1.28 gpf, and the ADA basics a plumber needs
- 15Materials and methods: PEX vs. copper vs. CPVC, ABS vs. PVC (it is regional), cast iron, and the transitions that fail
- 16Commercial basics: grease interceptors, the backflow program, and the tester certification that opens a second line of work
- 17Cal/OSHA for a small shop: the IIPP every employer must have, heat illness prevention, trenching and the 5-foot permit, confined space, silica, and ladders
- 18Environmental rules: EPA lead-safe certification for any pre-1978 home, asbestos and transite pipe, and stormwater
- 19Job-site craft: sequencing with the other trades, protecting the home, and the punch list that ends the job
- 20Case: the water heater that failed inspection twice
- 21Case: the gas leak call. The protocol, and the walk-away
- 22Case: the "customer doesn't want a permit" job
- 23Template: the job-site checklist, from the truck to the walk-through
- 24Template: the pre-inspection checklist by stage. Underground, rough, water heater final, gas, and trim
- 25Template: the Injury and Illness Prevention Program starter for a plumbing shop of one to five
- 26Template: the Heat Illness Prevention Plan for a plumbing shop, outdoor and indoor
- 27Template: the customer options sheet (good / better / best) with the cost band, the permit path, and the code trail on each rung