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FL Fixture Unit Calculator

FPC §604 supply sizing & §702 DWV sizing — residential & commercial

Florida Plumbing Code 2023
💧Water Supply Fixture Units (WSFU)
Enter the quantity of each fixture. WSFU values per FPC 2023 Table 604.3. The calculator totals WSFUs and recommends minimum supply pipe sizes per FPC §604.
Fixture WSFU Qty
Total WSFU 0
📊WSFU Reference — FPC Table 604.3
FixturePrivate (WSFU)Public (WSFU)
Toilet (flush tank)2.55.0
Toilet (flushometer)6.010.0
Lavatory / bathroom sink1.02.0
Bathtub (with shower)2.04.0
Shower stall2.04.0
Kitchen sink1.53.0
Dishwasher (domestic)1.5
Laundry tray1.53.0
Washing machine3.0
Hose bib (sillcock)2.55.0
Urinal (flush tank)3.0
Service sink3.03.0
Bar sink1.02.0
Ice maker0.51.0
Water softener1.0
📏Supply Pipe Sizing — FPC Table 604.4
Total WSFUMin Pipe SizeTypical Use
Up to 31/2 inchSingle fixture branch
4–63/4 inchSmall bath group
7–153/4 inchSmall residence
16–301 inchMedium home
31–601-1/4 inchLarge home / small commercial
61–1001-1/2 inchMulti-bath commercial
101–1802 inchMedium commercial
181–3002-1/2 inchLarge commercial
301+3 inch +Large commercial / multi-family
FL note: Water pressure in FL averages 65–75 PSI at the meter. Homes with PRV (Pressure Reducing Valve) at 70–80 PSI: use standard table values. Homes with street pressure under 50 PSI (common in older South FL neighborhoods): pipe one size up from table minimum to compensate for pressure loss at peak demand.
🚿Drain-Waste-Vent Fixture Units (DFU)
Enter fixture quantities. DFU values per FPC 2023 Table 702.1. The calculator totals DFUs and recommends drain, stack, and vent pipe sizes per FPC §702 and §906.
Fixture DFU Qty
Total DFU 0
📊DFU Reference — FPC Table 702.1
FixtureDFU ValueTrap Size
Toilet43"
Lavatory / sink11-1/4"
Bathtub21-1/2"
Shower stall22"
Kitchen sink21-1/2"
Dishwasher2(connects to KS)
Washing machine32"
Laundry tray21-1/2"
Floor drain22"
Urinal (wall hung)42"
Service sink33"
Bar / prep sink11-1/2"
Roof drainPer GPM
📏Drain Pipe Sizing — FPC Table 702.3
Pipe SizeMax DFU (Horiz)Max DFU (Stack)Max DFU (Building)
1-1/4"12
1-1/2"34
2"610
2-1/2"1220
3"204836
4"160240216
5"360540480
6"620960840
Drain Pipe SizeMin Vent SizeMax Vent Length
1-1/4"1-1/4"45 ft
1-1/2"1-1/4"60 ft
2"1-1/2"120 ft
3"2"180 ft
4"3"212 ft
6"4"300 ft
FL slab homes note: Most FL homes are slab-on-grade — DWV under-slab runs are cast before the pour and cannot be easily changed after construction. When sizing drain lines for a FL renovation, verify the existing under-slab drain sizes before adding fixtures. Adding a bathroom to a FL slab home is a significant job because the slab must be saw-cut and broken to run new drains.
📜FPC 2023 — Key Sizing Code Sections
SectionTopicKey Rule
§604.1Supply sizing generalSize all supply pipe per WSFU Table 604.3 for velocity max 8 ft/sec
§604.3Fixture unit tableWSFU values by fixture type and private vs public use
§604.4Supply pipe sizing tablePipe diameter by total WSFU demand
§604.6Velocity limitsMax 8 ft/sec in supply; max 4 ft/sec at final branch
§604.8Pipe supportCopper horizontal: 6 ft max; vertical: 10 ft max
§701.1DWV generalAll drainage by gravity unless approved ejector
§702.1DFU fixture tableFixture unit values by fixture type
§702.3Drain pipe sizingPipe diameter by DFU for horizontal, vertical, and building drains
§706.3Drain slopeMin 1/4" per foot for 3" and smaller; 1/8" acceptable for 4"+ with approval
§708.1Cleanout accessRequired at base of each stack and each 100 ft of horizontal drain
§906.1Vent pipe sizingMin vent by drain served; max vent length table per §906
§912.1Wet ventingPermitted in residential — limits on fixture type and count
⚠️Most Common FL Pipe Sizing Violations
3/4" supply main to full house: Many 1970s–1990s FL homes have undersized 3/4" copper mains. Acceptable then, but adding fixtures now triggers sizing upgrades per FPC.

S-traps: Widely used before 1990 in FL, S-traps are prohibited. Self-siphon risk. Inspector will flag during any WH or repipe permit.

2" drain for 3 toilets: Each toilet is 4 DFUs; a 2" horizontal drain maxes at 6 DFUs. Three toilets (12 DFUs) require a 4" drain — very common miscalculation in FL additions.

No cleanout at stack base: FPC §708 requires a cleanout at the base of each stack within 2 feet of where it changes from vertical to horizontal. Often missing in FL homes where the stack base is under the slab.

ABS pipe: ABS is prohibited in Florida — PVC Schedule 40 or DWV is required. ABS is legal in other states but FL inspectors will reject it.

Vent too small or missing: Each fixture branch must be properly vented. In FL slab homes, venting is often inadequate because adding vents requires going through the slab. Wet venting per §912 offers a workaround.
🏛️Commercial — County-Specific Notes
CountyCommercial Notes
Miami-DadeRequires structural engineer-stamped plans for commercial plumbing over $25K; separate MEP review from building structural; water department approval for mains >2"
BrowardFire suppression and plumbing must be submitted together for new construction; grease interceptor sizing requires Health Dept sign-off for food service
HillsboroughTampa Water Dept approval required for backflow on commercial mains; permits issued through HCBCC building portal; plan review 10–14 days standard
OrangeOrange County requires separate plumbing plan submittal for commercial; OC Utilities must approve tap for new water service above 1"
Palm BeachCommercial WH and supply pipe require licensed Mechanical and Plumbing Engineer of Record stamp for new buildings
🏠Typical FL Residential Fixture Unit Loads
Home TypeTypical WSFUsTypical DFUsMin Supply Main
2BR/1BA condo12–1614–183/4"
3BR/2BA single family20–2822–321"
4BR/3BA single family28–4030–451–1-1/4"
5BR/4BA large home40–6045–651-1/4–1-1/2"
Duplex (each unit)20–3022–351" per unit
Small commercial (1 restroom)20–3525–401–1-1/4"
📞Get a Free Pipe Sizing Consultation
Adding fixtures? Building an addition? Our licensed CFC plumbers will size your supply and DWV system per FPC 2023, pull the permit, and handle all inspections.
What Our Sizing Review Covers
✅ Total WSFU and DFU calculation per your fixture list
✅ Supply main and branch sizing per FPC §604
✅ DWV drain, stack, and vent sizing per FPC §702 + §906
✅ Existing system review — is current pipe undersized?
✅ Slab penetration plan (FL slab-on-grade homes)
✅ PRV sizing and pressure loss analysis
✅ Permit drawings and plan submittal
✅ County-specific commercial MEP coordination
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Florida Quick Answers

How much does fixture unit cost in Florida?

Costs vary by scope, home size, and your Florida region. Use the calculator above for a Florida-specific estimate rather than a one-size-fits-all price.

What affects the price?

Pricing depends on the size and layout of your home, the pipe materials and fixtures you choose, your Florida region and local labor rates, and permit fees. Work that is more complex or harder to access generally costs more.

Can I DIY this, or should I hire a licensed plumber?

In Florida, minor maintenance may be DIY, but anything beyond that generally calls for a licensed plumber, and many jobs require a permit and inspection. When a permit, or your main water or drain lines are involved, hire a Florida-licensed plumber.

Does homeowners insurance cover it?

It depends on the cause and your specific policy. Sudden, accidental damage is more often covered than gradual wear-and-tear or maintenance - confirm the details with your insurer.

How long does it take?

Timelines depend on scope - many routine jobs take a few hours to a day, while larger projects run longer. Your licensed plumber can confirm after assessing your home.

Plan with confidence

Planning estimate, not a quote — confirm with a licensed Florida plumber. Confidence is qualitative: ranges reflect this page’s Florida assumptions, not a guaranteed price.

Key assumptions

Estimates on this page are Florida-specific and reflect Fixture Unit Calculator for typical Florida homes.

From this page: Costs vary by scope, home size, and your Florida region. Use the calculator above for a Florida-specific estimate rather than a one-size-fits-all price.

Your actual cost depends on your home's condition, layout, and local labor and permit rates.

Factors that raise or lower cost

From this page: Pricing depends on the size and layout of your home, the pipe materials and fixtures you choose, your Florida region and local labor rates, and permit fees. Work that is more complex or harder to access generally costs more.

Generally raises cost: harder access, older homes, added permits and inspections, premium fixtures or materials, and emergency or after-hours work.

Generally lowers cost: easy access, bundling several items in one visit, standard fixtures, and off-peak scheduling.

Preparation checklist

  • Clear access to the work area and locate your main and fixture shut-off valves.
  • Check with your county or city building department (AHJ) on whether a permit and inspection are required.
  • Note the make, model, or measurements of existing fixtures and pipe materials.
  • Get the scope, total price, warranty, and cleanup terms in writing before work starts.
  • Verify the plumber holds an active Florida license and carries insurance.

Questions to ask your plumber

  • Are you licensed and insured in Florida, and who pulls the permit?
  • Is the quote itemized for parts, labor, permit fees, and disposal?
  • What could change the final price once the work begins?
  • What warranty covers the parts and the labor?
  • How long will the job take, and will my water be shut off?
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Curated Florida tools and resources related to this page.

Last reviewed: July 1, 2026 (US Eastern)

Reviewed by the FL Plumbing Tools editorial team.

Sources: Florida plumbing cost research and Florida Building Code / local authority-having-jurisdiction (AHJ) permit references.

Florida reference: Estimates and guidance reflect Florida labor rates, permitting, hard water, humidity, and coastal conditions.

Updates: Reviewed periodically and updated as Florida codes, permit fees, and market rates change.