We're replacing the kitchen line. Does the grease interceptor have to change too?

Check its size against Mobile's code before the work is permitted. The city's sizing formula uses seats, meal type, gallons per meal, retention time and hours open, with a 500-gallon floor and 1,000 gallons minimum on public sewer unless an Alabama-licensed design professional sizes it. A new sampling cleanout, one pipe size larger than the trap's outlet, goes right downstream of it.

Our site sewer is 8 inches. Can it be burst like a house line?

Not under the 2021 plumbing code that Mobile uses, which limits pipe bursting to gravity lines of 6 inches and smaller. Relining falls under a separate code section, which covers gravity pipe 4 inches and larger and has the code official review a recorded video of the line before a permit is issued. The ASTM standard for cured-in-place lining is written for pipe from 2 to 108 inches, but that is the standard's scope, not a city approval. An 8-inch line also needs manholes rather than plain cleanouts, which a quote should show.

We're opening an office in an old house. Does MAWSS need to see anything?

Yes. MAWSS policy says when a commercial operation moves into a formerly residential building, the owner must present plans and specifications for MAWSS review before it accepts fees or signs a service contract. A change of use can also bring added capacity fees. Ask the plumber to film the old lateral before the plans are drawn.

Commercial Sewer Line Replacement in Mobile, AL

Kitchen grease rule: Mobile's plumbing code requires interceptors for cooking establishments and every three-basin sink, at least 1,000 gallons on public sewer unless an Alabama-licensed designer sizes it.
Pipe size floor: a commercial building drain and a grease-waste main must be at least 4 inches under Mobile's amendments.
Big lines: building sewers of 8 inches and up need a manhole within 200 feet of the building and then every 400 feet under the 2021 code.
MAWSS grease fee (2025): food-service accounts pay a $30 monthly grease-management charge, plus a surcharge on oil and grease above 100 mg/l.

Mobile Sewer Line Replacement sets business owners up with an independent sewer contractor for work on commercial building sewers. Commercial lines differ from house laterals in the parts around them: grease interceptors and sampling cleanouts, larger pipe with manholes instead of cleanouts, and pavement over most of the run.

Commercial Sewer Line Replacement by Type of Business

The rules that change a commercial job come from three places: Mobile's plumbing code amendments, MAWSS's pretreatment program, and the state plumbing board's definition of where plumbing ends.

Opened concrete grease interceptor lid beside a new white PVC cleanout riser in an asphalt lot behind a small restaurant

Restaurants and Food Service: the Line to the Interceptor

Mobile requires properly sized interceptors for cooking establishments, the dumpsters that serve them, and all three-basin sinks. The grease-waste main has to be at least 4 inches, and a sampling cleanout sits right after the interceptor, one pipe size larger than its discharge. MAWSS places food businesses without a state discharge permit in its Category 2FS and tracks them for oil and grease, so a replaced line will feed a monitored system. Ask the plumber to price the interceptor connections and the sampling port with the line, not as extras.

Offices and Retail Strips Under Pavement

A commercial building drain must be at least 4 inches up to the first restroom group. Mobile's code keeps sewer pipe lighter than Schedule 40 pressure-rated out from under parking lots and vehicle paths, so a replacement under asphalt needs heavier pipe or a different route. Cleanouts in drive lanes use traffic-rated assemblies (cleanout rules).

Warehouses and Light Industrial Buildings

MAWSS sorts dischargers into categories. A business discharging more than 25,000 gallons a day of process wastewater generally falls under state permitting (Category 3); one whose wastewater carries something of concern to MAWSS but needs no state permit is Category 2I. Both have to provide, at their own expense, a monitoring point on the building sewer for inspection and sampling. When the building sewer is replaced, ask whether that monitoring facility has to move with it.

Concrete sewer manhole riser set in a gravel area beside a large metal warehouse, with a plain gray transit level on a tripod nearby

Large-Diameter Site Sewers, 6 Inch and Up

From 8 inches up, the 2021 code swaps cleanouts for manholes: one within 200 feet of the building and then at least every 400 feet. Cleanouts on 8-inch pipe need 36 inches of clear space in front of them. The state plumbing board says a non-residential sewer of 6 inches or more drawn on civil drawings sealed by an Alabama-licensed engineer isn't plumbing, so the largest site lines may be engineered utility work rather than a plumber's job. Bursting is out for pipe this size; see pipe bursting for the limit.

Gloved hands holding a sewer camera monitor showing a cracked clay pipe joint with roots, beside an open cleanout in a lawn

Why Mobile homeowners, landlords and businesses call Mobile Sewer Line Replacement

One licensed plumber gets the request, not a bidding list
No charge to you for the introduction
Ask to keep the camera video from before and after
Alabama plumbing licenses can be checked online

Who Signs Off on Commercial Sewer Work in Mobile

In Alabama only a master plumber can contract for the work (license checks). Around that sit the City of Mobile plumbing permit and inspection (details on the trenchless replacement page), MAWSS's review for new or converted commercial service, and an engineer's seal for multi-unit and larger site plans. Ask the plumber at the first visit which of these your job triggers.

Keeping a Business Open During a Sewer Replacement

No published survey gives commercial sewer prices for Mobile, and the national guides price house laterals; the homepage cost section has those figures. Ask for:

the hours the line will be out of service, in writing;
whether trenchless methods could keep the lot and entrance open (trenchless options);
a camera run of the existing line first, cleaned so grease doesn't hide the pipe wall.