Mop Sink / Service Sink Cost Estimator
A mop sink (also called a service or utility sink) is the low basin in the janitor's closet used to fill buckets and dump dirty water. Florida commercial buildings - restaurants, schools, offices, retail, medical - generally need at least one so wash water does not go down a restroom or kitchen fixture. The cost drivers are the basin type (a molded-stone floor mop basin vs a wall-hung service sink vs a heavy janitorial wash station), whether there is an existing rough-in or you are running new hot/cold supply and a drain, and add-ons like the hose-bibb faucet with a vacuum breaker (backflow), FRP wall panels, and an adjacent floor drain.
All three are "the utility sink," but they differ. A floor-mounted mop basin sits on the floor so you can roll or tip a bucket into it - molded stone or terrazzo, with a tiled or FRP splash. A wall-hung service sink is a deeper bowl mounted at counter height. A janitorial wash station is a heavier stainless setup for larger facilities.
Why It Matters
A floor mop basin is easiest on the back and best for bucket work; a wall-hung sink saves floor space; a wash station handles volume. The choice changes the fixture price and the rough-in height.
Building and health rules generally require commercial occupancies to provide a service/mop sink for janitorial use, so floors get mopped and buckets get emptied somewhere other than a restroom lavatory, a kitchen sink, or - worst of all - a floor drain or the parking lot.
Why It Works Here
Florida restaurants, schools, gyms, clinics, and retail all fall under these expectations. A correctly plumbed mop sink with backflow protection keeps wash chemicals out of the potable system and keeps an operation inspection-ready.
Mop sink faucets almost always have a threaded hose connection so a hose can be attached - and a hose sitting in dirty mop water is a textbook cross-connection. That is why a service-sink faucet needs an atmospheric vacuum breaker or equivalent backflow protection.
FL Notes
This is one of the most common items an inspector checks on a mop sink. The required device and its height above the flood rim follow the adopted plumbing code; confirm the specifics with your AHJ.
A service sink needs a trapped, vented drain and usually both hot and cold supply. Floor-mounted basins drain low, so the trap and outlet location have to be planned before tile or FRP goes up.
FL Slab Reality
Most Florida commercial space is slab-on-grade, so a new drain often means core-drilling and trenching the slab - a real cost. Where that is impractical, the layout is planned around the nearest existing waste and vent. An unvented trap is a frequent miss.
The janitor's closet around the sink matters. FRP (fiberglass-reinforced plastic) wall panels behind and beside the basin give a cleanable, water-resistant splash surface, and a mop/broom hanger rail keeps tools off the wet floor.
Why FL Cares
Humidity and constant wetting make untreated drywall behind a mop sink a mold problem fast. FRP panels and a proper splash guard are cheap insurance, and they are commonly expected in food-service and healthcare closets.
Best Time: During Build-Out
Set the drain, trap, vent, and hot/cold stub-outs while the slab is open and the walls are framed - the cheapest path for a new mop sink.
Typical Install
1. Confirm basin type, location, and the drain/vent route. 2. Rough in the trapped, vented drain and hot/cold supply. 3. Set the floor basin (or hang the wall sink) level and secure. 4. Install the hose-bibb faucet with its vacuum breaker. 5. Add FRP panels, splash guard, and mop hanger. 6. Test fill, drain, and the backflow device.
FL Gotchas
No vacuum breaker on the hose faucet, an unvented trap, skipping FRP behind the basin, and underestimating slab core-drilling for a new drain.
A mop sink takes abuse - grit, chemicals, and constant wetting. A little upkeep keeps it draining and sanitary.
Routine Care
Clear the strainer and trap of mop strings and grit, rinse the basin and FRP, and check that the vacuum breaker is intact and the faucet is not leaking. Keep the floor drain (if present) clear too.
Warning Signs
Slow drainage, sewer odor (a dry or unvented trap), a dripping or missing vacuum breaker, and water-stained or soft wall behind the basin all need attention.
The basin is only part of it - the rough-in, the drain, and any slab work usually drive the total. These are planning estimates for the work plus professional labor in the FL market.
Type & Situation
A same-spot replacement is the low end; a new basin needing hot/cold supply, a trapped/vented drain, and slab core-drilling is the high end. A heavy wash station costs more than a basic mop basin.
Run & Add-ons
Long runs and slab drilling, the vacuum-breaker faucet, FRP panels, and an added floor drain each add. Use the calculator to combine sink type, install situation, run, and add-ons.
FL Permit Requirements
- Swapping a service/mop sink for the same type in the same spot
- Replacing a service-sink faucet or its vacuum breaker
- Adding FRP panels or a mop hanger to an existing closet
- New hot/cold supply and a trapped, vented drain for a mop sink
- Core-drilling or trenching a slab for a new drain
- Adding an adjacent floor drain
- Commercial build-out and food-service / healthcare fit-outs
FL County Permit Fee Reference
Swapping a service sink or faucet in place is usually minor. Running new hot/cold supply and a trapped/vented drain, core-drilling a slab, or adding a floor drain is regulated work that is often permitted, and commercial build-outs and food-service/healthcare projects can trigger additional review. Fees and timelines are approximate — verify with your local building department / AHJ before starting work.
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FL Code References
Who Can Pull a Permit in FL?
Running new hot and cold supply, a trapped and vented drain, and the backflow protection (vacuum breaker) for a service/mop sink is regulated plumbing work that often requires a permit, and core-drilling or trenching a slab for a new drain is part of that work. Drain venting, hose-faucet backflow protection, and any added floor drain follow the adopted plumbing code and local amendments, and commercial build-outs are generally permitted and inspected. A like-for-like service-sink swap or a faucet replacement is usually minor. Per FL Statute 489.105, regulated plumbing and related construction work is performed by the appropriate licensed contractor.
Verify any contractor's license at myfloridalicense.com and confirm requirements with your local building department before work begins.
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Licensed FL Contractor - Service Sinks, Mop Basins & Backflow
We install and replace mop and service sinks for restaurants, schools, offices, retail, and medical spaces — floor-mounted mop basins, wall-hung service sinks, and janitorial wash stations — with hot and cold supply, a trapped and vented drain, the hose-bibb faucet and vacuum breaker Florida code calls for, FRP splash panels, and an adjacent floor drain when you need one.