Pressure washing in Philadelphia: old brick, historic rules and storm drains

Updated November 10, 2026 · KeystoneProGuide editorial team

What should Philadelphia homeowners know before a pressure wash?

A large share of Philadelphia's houses are old, and the city has rules of its own that reach washing. The Census Bureau estimates that 39.9 percent of the city's 748,270 housing units were first built in 1939 or earlier, against 25.0 percent for Pennsylvania. Age raises two separate questions here, lead paint and the condition of old masonry, and the city adds a third: whether your house is on the historic register.

Does washing a historic Philadelphia house need approval?

It can. For a property on the Philadelphia Register of Historic Places, the Historical Commission says review is required for masonry cleaning, painting, pointing, repair, replacement, alteration or removal, and for painting, coating, staining or sealing any surface except wood and metal trim. Standard maintenance, such as scraping and painting wood trim or cleaning gutters, does not need review.

Reviews are free, and the commission's staff can be reached at preservation@phila.gov during planning; the city says staff often approve applications without sending them to the full commission. If you are not sure whether your house is on the register, ask before the brick is washed, not after.

How gently should old brick be cleaned?

More gently than most machines run. The National Park Service recommends a low-pressure spray of 100-400 psi, the wand at least 12 inches away, and a test in an inconspicuous spot, and says most hardware-store washers operate at 1600-3200 psi. It adds that low-fired historic brick tends to have a soft, porous interior beneath the protective fire skin, and that lime-based mortars are sensitive materials. In a city where four homes in ten pre-date 1940, that caution applies to a large share of the housing.

What about lead paint on a row house?

Every house in that 39.9 percent pre-dates the 1978 ban on lead paint for homes, and so do many built later. The U.S. Environmental Protection Agency (EPA) requires a paid company that disturbs painted surfaces on a pre-1978 home to be certified in lead-safe work. Its archived answer on washing says the work area must be contained so that no dust or debris, including in the waste water, leaves it.

The rule matters more in a city where so many homes are rented. The Census Bureau puts 48.2 percent of Philadelphia's 679,428 occupied homes as renter-occupied, and the EPA says the rule applies to landlords who disturb paint in pre-1978 rentals.

Where does the wash water go in Philadelphia?

Often into a combined sewer. The Philadelphia Water Department says its combined sewer system serves about 60 percent of the city, and that in wet weather that older part of the system often overflows, sending stormwater and diluted sewage into local waterways. The department says storm drains lead to streams and rivers, and its guidance is plain: only rain should go in storm drains, and mop water and vehicle oil should stay out. The department maintains more than 72,000 inlets; report a clogged one on (215) 685-6300 or ask for a cleaning through 311.

Does a washing company need a city license?

Usually not, if it works only on houses. The city requires a Contractor License for construction, demolition and repair businesses, but says a business that works only on existing one- or two-family homes, and is not a plumber, electrician, fire suppression or complete demolition contractor, must register with the state as a home improvement contractor instead. The city's license page does not mention washing. Its lookup tool lists every actively licensed contractor and any licensing violations, and 311 handles questions, or (215) 686-8686 from outside the city.

For the state registration, use the Attorney General's contractor search set to Philadelphia; it offers "Pressure Washing" as a type of work, though the data is still limited. What Pennsylvania requires explains how far registration reaches, and how to choose a pressure washing company covers the questions on method. Businesses serving the city are on the Philadelphia pressure washing page.

Sources

1. 2020-2024 ACS 5-Year Narrative Profile: Philadelphia County, Pennsylvania, U.S. Census Bureau
2. 2020-2024 ACS 5-Year Narrative Profile: Pennsylvania, U.S. Census Bureau
3. Lead Renovation, Repair and Painting Program, U.S. Environmental Protection Agency
4. How do RRP requirements apply to pressure washing? What containment and other preparation are required?, U.S. Environmental Protection Agency (January 2025 archived copy)
5. Preservation Matters: Maintenance - Graffiti Removal from Historic Features, National Park Service
6. Protecting Historic Structures from Oil Contamination, National Park Service
7. Get approval for work to a historic property, City of Philadelphia
8. Taking Care of Storm Drains, Philadelphia Water Department
9. Green City, Clean Waters, Philadelphia Water Department
10. Find a licensed contractor and contractor information, City of Philadelphia
11. Get a Contractor License, City of Philadelphia
12. Home Improvement Contractor Search, Pennsylvania Office of Attorney General