Who is responsible for a clogged shared sewer line in a strip mall?

Strip Mall Shared Sewer Clog: Who Pays?

Quick Answer

Check the lease first. In most strip malls the landlord handles a clog in the shared drain or building sewer, often passing the cost to tenants through common area charges, while each tenant handles pipes serving only its own suite. A tenant whose grease or misuse caused the clog can be billed. Find the blockage's location before assigning anything.

Which part of the sewer is shared?

The plumbing code gives the pieces names, and the names map onto a strip mall. The International Plumbing Code, as adopted in Phoenix, defines a branch as "A drain serving two or more fixtures that discharges to another drain or to a stack," and the building sewer as "That part of the drainage system that extends from the end of the building drain and conveys the discharge to a public sewer, private sewer, individual sewage disposal system or other point of disposal." Phoenix's amendments in Ordinance G-7397 change the grease interceptor definitions in that chapter but not these.

In a typical center, each suite has its own fixtures and a branch that runs to a shared line under the slab or behind the building. That shared line, often called the main or the building sewer, serves several suites and runs to the city's sewer. It is common to the whole center, not to any one tenant.

Where the blockage is	Who usually deals with it	Why
A fixture, trap or branch serving one suite	That tenant, subject to the lease	Serves only that suite
The shared line under the center, shared cleanouts	The landlord, often with a charge-back	Serves several suites
A shared grease interceptor	The property owner under Phoenix's FOG rules	Multiple users
The city main in the street	The city	Public sewer

Treat the table as a starting map. The lease can move any row.

How do you tell where the blockage is?

Start with who is affected. If only one suite is backing up, the problem is probably its own branch. If several suites are, and the lowest floor drains or toilets overflow first, the shared line is the suspect. Our guide to telling a main line clog from a single drain clog explains the pattern, and tracing a sewer smell in a strip mall covers the mapping method.

A plumber confirms the location with the nearest cleanout and a camera. The video and the footage mark are the most useful record you can have, because they show whether the blockage is grease, roots, wipes, a broken pipe, or something else, and which suite's branch joins nearby.

What does the lease say about who pays?

Look at the repair, maintenance, and common area clauses. Holland & Knight explains that "A NNN lease is a lease where the landlord passes all expenses incurred by the landlord in connection with operating the property through to the tenant," and that "NNN leases are most common in retail spaces." So in a retail center the landlord may do the work on the shared line, then bill every tenant its proportionate share as part of common area costs. The same firm adds a review tip: "Under an NNN lease, the landlord may still be required to repair major structural defects and/or be responsible for capital expenditures above a certain threshold." A collapsed section of pipe may fall in that category, while a routine jetting does not.

Under a gross lease the landlord generally keeps the maintenance cost inside the rent, so a shared-line clog is the landlord's expense unless the lease says otherwise. Our page on commercial plumbing repairs: tenant or landlord walks through the lease types, and who pays for a sewer smell in a commercial lease explains why Arizona's residential landlord and tenant statute does not decide a commercial dispute.

What if one tenant caused the clog?

Then the lease's indemnity and damage provisions may let the landlord charge that tenant, and other tenants may ask for it. Restaurants are the usual case. Grease cools in the shared line and builds up, and a camera that shows heavy grease starting where one restaurant's branch joins is strong evidence.

Phoenix places the grease interceptor duties with the user, or with the owner when several users share one. Its FOG manual says "Maintenance of grease interceptors is the sole responsibility of the user, or in the case of multiple user interceptors, the property owner." It also says records "need to be available on site for three years," and that the user or owner must be able to give the city documentation showing maintenance frequencies are being met. If your center shares an interceptor, ask the landlord for those pumping records. Our page on pumping, cleaning and jetting explains why pumping the trap does not clean the lines downstream.

Disputes over blame and money are contract questions, and Arizona commercial leases rest on what the parties signed. Keep emails factual, keep the video, and ask an attorney before withholding rent or billing another tenant.

What should you do while it's backed up?

1Notify the landlord or property manager in writing with the time, the suites affected, and the fixtures that are overflowing. Check the lease for notice and emergency repair language.
2Stop water use in the affected suites so sewage does not keep rising.
3Call a licensed plumber to clear and camera the line, and ask for a written note of where the blockage was and what it was.
4Document losses and cleanup. Photos, dates, and receipts support insurance and any lease claim. See what first for a sewer backup in a multi-tenant building.
5Do not pay a disputed charge-back before reading the common area clause and the invoice. Ask the landlord for the plumber's report.

HQ jets and cameras building drains and restaurant laterals, including before opening or after close, so the work does not cost a tenant its service hours. We are licensed and insured, with upfront pricing and free estimates. This page explains general guidance and is not legal advice. Your lease controls.