Florida grey water regulations allow you to reuse water from baths, laundry, lavatories, and non-kitchen sinks for subsurface irrigation or for flushing toilets and urinals, but they prohibit any surface discharge onto the ground or into state waters, require a permit for systems tied to onsite sewage treatment, and impose treatment, dye, and setback standards through the Florida Building Code. The rules sit across several statutes and codes, and the agency that enforces them is currently shifting from the Department of Health to the Department of Environmental Protection on a county-by-county schedule.
What Counts as Grey Water in Florida
Florida Statute 381.0065 defines grey water as the portion of domestic sewage that is not black water — wastewater from your bath, lavatory, laundry, and non-kitchen sinks.1Florida Senate. Florida Code 381.0065 – Onsite Sewage Treatment and Disposal Systems Regulation Kitchen sink waste is not grey water. It’s classified as black water alongside toilet and urinal waste because kitchen drains carry grease, food particles, and organic loads that are harder to treat safely at the residential level.2The Florida Legislature. Florida Code 381.0065 – Onsite Sewage Treatment and Disposal Systems Regulation
That distinction has practical consequences. A grey water reuse system must be entirely separate from the septic or black water system. If a kitchen drain gets tied into a grey water line, the water no longer qualifies under Florida law and the system won’t meet the applicable standards.
Where You Can and Cannot Use Grey Water
Residential reuse falls into two permitted categories: flushing toilets and urinals, and subsurface landscape irrigation. Both are allowed under the Florida Building Code. Direct surface discharge is prohibited. You cannot run a washing machine hose onto the lawn. Irrigation has to be applied below the surface so the soil filters the water naturally.
Treatment and Storage Standards
Chapter 13 of the 2023 Florida Building Code (Plumbing) sets the technical rules for nonpotable water reuse. When grey water is reused for flushing toilets and urinals, it must be disinfected and treated by an onsite water reuse treatment system that complies with NSF/ANSI Standard 350.3US EPA. Summary of Florida’s Water Reuse Guideline or Regulation for Onsite Non-Potable Water Reuse Untreated grey water in a collection reservoir cannot sit for more than 24 hours. Earlier editions of the code allowed up to 72 hours, so systems designed under the old rule need to be checked against the current one.
Grey water intended for flushing must be dyed so it’s visually distinguishable from potable water. The plumbing for the grey water side has to stay completely separate from the potable supply and from the black water drainage. Storage tank overflow pipes must be trapped and indirectly connected to the sanitary drainage system, so any excess routes back into the sewer rather than pooling or surfacing.
Setback Distances
Storage tanks for grey water reuse systems must sit at least 50 feet from water wells and from streams or lakes, at least 10 feet from a public water main, and at least 5 feet from property lines, septic tanks, and seepage pits.
For grey water systems tied to onsite sewage treatment, the statutory setbacks under 381.0065 apply: at least 75 feet from a private potable well, 75 feet from tidal surface waters, and 15 feet from stormwater retention areas designed to hold water for less than 72 hours after rainfall.2The Florida Legislature. Florida Code 381.0065 – Onsite Sewage Treatment and Disposal Systems Regulation Public potable wells serving facilities with more than 2,000 gallons of daily sewage flow require a 200-foot setback. These are floors. A site evaluation can push them wider.
Permitting and Which Agency Handles It
Residential grey water systems connected to an onsite sewage treatment and disposal system require a modification permit. You apply through your county health department or, in counties that have already transitioned, through DEP. The application needs a site plan showing the structure, the grey water layout, the potable water source, and every setback distance.
A site evaluation is mandatory. It assesses soil conditions, water table depth, and other factors that determine whether the property can support the system. DEP staff or a qualified private site evaluator can perform it. Total fees for a residential OSTDS modification — application, site evaluation, and permit issuance combined — run about $570, and may vary slightly depending on when a county transitions to DEP administration.
The transition itself matters if you’re applying today. The 2020 Clean Waterways Act moved the onsite sewage program from DOH to DEP in phases. Sixteen Northwest Florida counties (Escambia through Jefferson) went to DEP permitting on January 2, 2025, with Marion County following in July 2025.4Florida Department of Environmental Protection. Onsite Sewage Program – Program Update – Phase I Transition The remaining counties are expected to transition through December 2026.5Florida Department of Health. Onsite Sewage Treatment and Disposal System Transition Your county health department can confirm which agency currently handles permits in your area.
Commercial and Industrial Systems
Grey water systems at commercial facilities, laundromats, and industrial operations that exceed residential scale fall under DEP jurisdiction rather than the onsite sewage program. Under Florida Statute 403.088, anyone discharging waste into state waters must obtain an operation permit from DEP, and the department must find “reasonable assurance” that the discharge won’t violate water quality standards before issuing it.6Florida Senate. Florida Code 403.088 – Water Pollution Operation Permits Conditions
Facilities that send grey water or other wastewater to a publicly owned treatment works, rather than directly to surface water, must also comply with federal pretreatment standards under 40 CFR Part 403.5, whether or not the local treatment works runs an approved pretreatment program. Those rules prohibit discharges that cause “pass through” or “interference” with the receiving plant.7US EPA. Pretreatment Standards and Requirements – General and Specific Prohibitions A laundromat or car wash sending high-volume grey water into a municipal sewer is subject to these rules even though the water started as grey water rather than industrial waste.
Boats and Vessels
Grey water rules for land-based systems do not carry over to vessels the way many boaters expect. Under Florida law, grey water discharged from vessels — defined as galley, bath, and shower water — is not classified as “sewage,” and its release into state waters is not currently prohibited.8Florida Department of Environmental Protection. Vessel Discharge Raw sewage discharge is a different matter and is illegal in state waters, which extend three nautical miles from shore on the Atlantic coast and nine nautical miles on the Gulf side.9Florida Fish and Wildlife Conservation Commission. Boundary Maps and Management Zones
Vessels 26 feet or longer with an enclosed cabin and berthing must have a toilet, and any permanently installed toilet must connect to a U.S. Coast Guard-certified marine sanitation device. Houseboats must use a Type III MSD (a holding tank), and if plumbing allows overboard discharge, the valve must be locked to prevent it while in state waters.10The Florida Legislature. Florida Code 327.53 – Marine Sanitation In designated No Discharge Zones, all sewage discharge is prohibited, treated or not. Florida Statute 327.521 designates state waters within aquatic preserves as No Discharge Zones upon EPA approval.11The Florida Legislature. Florida Code 327.521 – No-Discharge Zones
Developer Density Bonuses
Florida Statute 403.892 requires counties, municipalities, and special districts to offer density or intensity bonuses to developers and homebuilders who install grey water systems. A 25% bonus applies if at least 75% of the homes in the development will have grey water systems. The bonus rises to 35% if every unit includes one. These stack on top of any local density bonuses already available.12The Florida Legislature. Florida Code 403.892 – Incentives for the Use of Graywater Technologies
The development must include at least 25 detached single-family homes or 25 multifamily dwelling units, and the developer must certify compliance as part of the application for development approval. A pending 2026 legislative amendment would modify the building height limitation for eligible multifamily projects.13Florida Senate. Florida Senate Bill 1510 – Amendment 376678
Penalties for Unpermitted Discharge
Administrative penalties under Florida Statute 403.121 are tiered:
- $2,000 for failure to obtain a required onsite sewage treatment and disposal system permit or a wastewater permit other than one for surface water discharge.
- $4,000 for an unpermitted or unauthorized domestic wastewater discharge that does not result in a surface water or groundwater quality violation.
- $10,000 for an unpermitted or unauthorized discharge that causes an actual surface water or groundwater quality violation.
Each day an unauthorized discharge continues counts as a separate offense, so administrative fines compound quickly.14The Florida Legislature. Florida Code 403.121 – Judicial Remedies and Administrative Penalties On the civil side, DEP can go to court to recover up to $15,000 per offense per day.
Criminal exposure runs higher. A willful violation of Florida’s environmental statutes is a third-degree felony carrying up to $50,000 in fines, five years of imprisonment, or both per offense. A violation committed through reckless indifference or gross careless disregard is a second-degree misdemeanor punishable by up to $10,000 in fines and 60 days in jail. A lesser willful violation of a DEP rule or permit condition is a first-degree misdemeanor with up to $10,000 in fines and six months in jail.15Florida Senate. Florida Code 403.161 – Penalties With the per-day multiplier, even a brief period of noncompliance can generate substantial liability.