What happens to the runoff from roof cleaning?

“In all cases, the water used must drain to a pervious surface or to a water recycling/reuse system.” That is the whole sentence, as Collier County 311 publishes its summary of Ordinance 2015-27, and it gives the water two places to go.

The sentence follows the summary's washing line, which allows car, truck and boat washing and “the washing of exterior home surfaces and roofs” anytime with low-volume equipment or a self-canceling hose nozzle, so a roof wash is among the uses it covers. How the washing line reads as a water-use rule on a roof job is set out with the Florida rules that touch a roof cleaning.

Read quickly, the sentence is easy to shorten to a rule that the rinse water belongs in the ground. The county did not write that. A pervious surface is one of two destinations; a water recycling or reuse system is the other, and the summary joins them with a plain “or”. The summary defines neither term, and no Florida statute or rule read for this answer defines “pervious surface” at all. The 311 article is silent on whether the ordinance covers addresses inside the cities.

A second county instrument reaches the same ground the drainage sentence sends water to. It is the Water Pollution Control and Prevention Ordinance, codified in Chapter 54 of the county code.

Sec. 54-67 opens “Discharge of Pollutants is prohibited” and its list of places a pollutant may not be discharged runs from surface water, canals and bays through ground water and wetlands to “onto the ground, or into a Stormwater Management System (SMS).” The ordinance defines a pollutant broadly, as “a substance that alters the chemical, physical, biological, thermal and/or radiological integrity of soil, stormwater, ground water or Surface Water.” Soil is in that definition by name.

The two county sentences come from different instruments. Neither is a finding about any one property: the drainage sentence does not say a lawn makes wash water acceptable, and Sec. 54-67 does not say what a roof wash's water contains. The washing rule names where the water drains; Sec. 54-67 limits what may be discharged onto the ground it reaches.

Where the pollution code applies matters as much as what it says. Sec. 54-64 says its provisions “apply to, and be enforced in, the unincorporated areas” of the county; a city inside the county comes under it only by a resolution of its own governing body, and the code as read does not establish one for Naples, so that is the city's to confirm. Naples has its own chapter: Sec. 42-5(a) defines a pollutant to include “detergents or surfactants used to disperse other pollutants,” and Sec. 42-5(b) bars discharging pollutants into the city's waterways, drainage ditches and stormwater conveyance system.

Two state sources describe wash water sent to grass or bare ground, and both put limits on it. Neither was written about roofs.

The Florida Department of Environmental Protection's document is titled “Recommended Best Management Practices for Mobile Vehicle and Equipment Washing.” It says its practices may be used for any mobile washing activity, but that they are “specifically intended to provide guidance for fleet vehicle and heavy equipment washing.” It is guidance FDEP recommends, not an FDEP rule for house or roof washing, and it is quoted here only as that.

Within that scope, FDEP writes that discharges to the ground must be treated to prevent ground water pollution, and that a grassy surface can provide that treatment for small and infrequent discharges, small meaning “minimal ponding and no runoff.” Where wastewater is diverted to landscaped areas, FDEP says damage to plants and soil can be avoided by minimizing or eliminating soaps, detergents and chemicals. In some areas, such as those over sole source aquifers, discharge to ground may not be allowed or may require further controls.

FDEP's ninth practice leans away from the county's sentence: cosmetic vehicle or equipment washing “should be performed on an impermeable surface” where available, so the water can be collected. That is a vehicle-washing document preferring collection, beside a county summary naming a pervious surface or a recycling system. They are different documents with different scopes, and this answer does not merge them into one instruction.

UF/IFAS Extension's homeowner publication on stormwater pollutants, SL507/SS720, adds the plainest limit. It says soaps and detergents in stormwater runoff can impair receiving waters, and that wash water carrying phosphate or similar cleaners should not be allowed to soak into the ground “at all, if possible.” Its washing example is a car on gravel or grass, where the water gets a chance to be filtered first. What a cleaning solution does to the shrubs it lands on is a separate question, taken up in whether roof cleaning hurts plants.

Every source above is general. None of them measures the water that comes off a roof during a soft washing.

FDEP lists what wash water from vehicle and equipment cleaning can contain: oil and grease, petroleum products, dirt and grit, heavy metals, detergents and other pollutants. That list describes vehicles and equipment. No document read for this answer publishes a comparable list, or a test result, for the rinse off a roof, and this page does not supply one.

What the roofing trade does publish is a precaution. ARMA tells anyone applying its chlorine bleach solution to asphalt shingles: “Take proper precautions to protect landscaping and surrounding areas from the chlorine bleach solution.” That is ARMA's instruction for its own shingle procedure, and the steps the trade describes around the house are laid out under what sits under the roof during a soft wash.

The path the water takes follows the roof's shape. Runoff from roof cleaning leaves at the eaves and the downspouts and lands on whatever is below: a planting bed, a lawn, a walkway, or a driveway that carries it on toward the street. What happens where it crosses pavers is its own question, answered in whether roof cleaning can stain pavers, and what happens where it meets a grate at the curb belongs to whether wash water goes into the storm drain.

No source read for this answer says whether the runoff at a given house is a pollutant or a violation, and neither does this page. The instruments do say who decides.

• Unincorporated Collier: whether runoff that reached the ground carried a pollutant is for the county's Pollution Control section.
• The City of Naples: the city is the one to say whether Chapter 54 reaches its addresses, and its pollution prevention page, as archived in 2022, sends pollution reports to Code Enforcement at 239-213-5030.
• Marco Island, Estero or Bonita Springs: Marco Island, like Naples, comes under Chapter 54 only by a resolution of its own, and none was read for this answer. Estero and Bonita Springs are outside Collier altogether, and which water rules cover exterior cleaning in the four named places is answered separately.
• Wash water sent to land: FDEP or the local environmental program, whose authorizations and permits are set out under whether exterior cleaning needs a permit.

A cleaner does not rule on whether runoff is clean, and a reading of the codes does not settle an enforcement question. Both belong to the offices above.