Backwater Valves for Commercial Buildings in Ohio: When the Code Requires One

By the ACC Solutions team

In Ohio, a commercial building needs a backwater valve only when the Ohio EPA or the local sewer purveyor requires one, and then only for plumbing fixtures on a floor that sits below the manhole cover of the next upstream manhole in the public sewer. That is Ohio's own wording, not the model code's: the state rewrote that section of the plumbing code. This guide explains the rule, the measurement that decides it, and the order to work in if your basement restrooms, floor drains or laundry are at risk of sewer backup. For the pipe from your building to the street, see our guide to sewer lateral repair on a Cleveland commercial property, and for ACC's plumbing work, see commercial plumbing services.

What Ohio's plumbing code says about backwater valves

The Ohio Plumbing Code is the 2021 International Plumbing Code as adopted and changed by the state. The changes to the drainage chapter are in Ohio Administrative Code 4101:3-7-01 (effective October 15, 2025). It replaces model section 714.1 with this:

"If required by the 'Ohio Environmental Protection Agency' or local sewer purveyor, a backwater valve is to be installed only for plumbing fixtures installed on a floor with a finished floor elevation below the elevation of the manhole cover of the next upstream manhole in the public sewer..."

Three things follow from that sentence and the rest of the section:

1. The trigger is a requirement from Ohio EPA or the sewer purveyor. In Ohio, the code itself doesn't make every low floor need a valve. It points you to whoever runs the sewer.
2. Only the low fixtures get protected. Fixtures on a floor below that manhole cover are protected by a backwater valve in the building drain or the horizontal branch serving them.
3. Upper fixtures must bypass it in new work. Fixtures on floors above the manhole cover "shall not discharge through a backwater valve." The reason is practical: if the valve closes during a surcharge, the upstairs restrooms keep draining into the lower floor. The rule has one exception: in existing buildings, fixtures above that elevation are not prohibited from discharging through a backwater valve.

The same Ohio rule also says the city engineer's department, the board of health or the sewer purveyor "has complete supervision and regulation" of the sewerage system, "including the building sewer and all laterals draining into the street sewers." So the sewer owner is the first call, not the last.

Step 1: Ask the sewer purveyor what they require

Find out who owns the sewer your building drains to and whether it requires backwater protection for your situation. In Cleveland that is the Division of Water Pollution Control (WPC), 12302 Kirby Avenue, 216-664-2513. Most suburbs run their own local sewers through the city engineer or service department. Ask three questions, and write down who answered:

• Do you require a backwater valve for fixtures below the upstream manhole?
• Is there a required device type or location (inside the building drain or at the lateral)?
• Do you issue a separate permit for work on the building sewer or in the tree lawn?

If sewage has already backed up, WPC's own brochure says to contact WPC to investigate first. If the main sewer is flowing properly, you'll need a licensed and bonded plumber to clear your connection, and repairs between the building and the curb are the owner's responsibility (WPC sewer-related problems brochure). WPC's glossary describes the lateral as "the property and responsibility of the homeowner or business owner" (WPC terminology).

Step 2: Compare your lowest floor to the upstream manhole cover

The code's test is an elevation comparison: the finished floor where the fixtures sit versus the rim of the manhole cover on the next manhole upstream of your connection in the public sewer. Upstream matters because that is the manhole that would overflow first if the main backs up. You'll usually need a survey or a level shot from a contractor or engineer to compare the two, plus the sewer owner's map to know which manhole counts. Write the numbers on the drawings; reviewers and inspectors will want to see how you decided.

Step 3: Split the drainage so only the low fixtures go through the valve

In new construction or a gut rehab, design the building drain so the fixtures below the manhole elevation run through the backwater valve and the upper floors join the drain downstream of it. In an existing building, the Ohio exception allows upper fixtures to stay on the protected line, which can avoid tearing up a slab, but it also means a closed valve stops the whole building from draining. On a multi-story building, weigh that trade-off before choosing the cheaper layout. Our multifamily plumbing page covers apartment buildings, where the upper floors are many units.

Step 4: Permit, inspection and the right contractor

A backwater valve installation is plumbing work on the building drain and needs a plumbing permit from the city where the building sits. In Cleveland, the Department of Building and Housing issues plumbing permits, and contractors must be bonded, state-licensed and registered with the city. If the work goes past the building into the tree lawn, WPC's brochure says licensed and bonded sewer builders must get a sewer repair permit from WPC at its Kirby Avenue office before digging. Don't cover the work until it has been inspected; see what to do after a failed commercial plumbing inspection if it doesn't pass the first time.

Sump pumps and sewage ejectors are a separate rule

Fixtures too low to drain by gravity often go to a sewage ejector instead. Ohio changed that section too: in buildings where the Residential Code of Ohio applies, only a check valve is required on the pump or ejector discharge piping. That exception is for residential-code buildings, so commercial buildings follow the commercial code text; confirm the required valves with your designer and the plumbing inspector. A check valve on a pump discharge and a backwater valve on a gravity drain do different jobs, so ask which one your low floor needs.

Mistakes that cost owners money

• Assuming every basement needs a valve, or that none do. In Ohio the answer comes from the sewer purveyor and the elevation, so ask and measure before you design.
• Running the whole building through the valve in new work. Ohio's rule says fixtures above the manhole elevation shall not discharge through it.
• Hiring a plumber before calling WPC after a backup in Cleveland. WPC's brochure says that if the problem is between the curb and the main sewer and you hired a plumber first, you need a receipt noting the exact location of the problem to bring to WPC.
• Burying the valve where nobody can reach it. A backwater valve is a mechanical device. Debris can keep it from closing, so plan access for inspection and cleaning, and put it on the building's maintenance list.
• Pouring grease down basement drains. WPC warns that grease clogs sewers and that pouring it into the sewer or a catch basin can bring fines of up to $1,000 per occurrence. Kitchens need proper grease handling; see commercial grease interceptor requirements in Cleveland.

Get a backwater valve scoped for your building

ACC Solutions coordinates commercial plumbing for storefronts, restaurants, offices and apartment buildings and quotes after a walkthrough. Send the address, what's on the lowest floor (restrooms, floor drains, laundry, a kitchen), any history of backups and anything the sewer owner told you. Call the plumbing desk at (216) 480-8899 or request a plumbing project review. To make the visit count, see how to prepare for a commercial plumbing walkthrough. This article is general information, not engineering or legal advice; the sewer owner and your building official have the final word.

ACC Solutions team
Phone: (216) 238-5999 · Email: support@accmgmtsolutions.com · Contact form
6545 Market Ave N, Canton, OH 44721

Frequently Asked Questions

Does Ohio require a backwater valve in a commercial building?

Only if the Ohio EPA or the local sewer purveyor requires one. When required, it protects plumbing fixtures on a floor whose finished elevation is below the manhole cover of the next upstream manhole in the public sewer (OAC 4101:3-7-01, section 714.1 as modified).

Can upper-floor fixtures drain through a backwater valve in Ohio?

Not in new work. Ohio's rule says fixtures on floors above the upstream manhole cover elevation shall not discharge through a backwater valve. In existing buildings, it is not prohibited.

Who do I call about sewer backup in a Cleveland building?

Cleveland's Division of Water Pollution Control at 216-664-2513. Its brochure says WPC can investigate the main sewer; if the main is flowing properly, a licensed and bonded plumber clears the owner's connection.

Do I need a permit to install a backwater valve in Cleveland?

Yes, it is plumbing work on the building drain, so the Department of Building and Housing issues the plumbing permit. Digging in the tree lawn to repair a sewer also needs a WPC sewer repair permit.

How does ACC price backwater valve work?

After a walkthrough. Call the plumbing desk at (216) 480-8899 or request a plumbing project review, and send the address, what is on the lowest floor and any backup history.