San Diego County

The San Diego Regional Water Quality Control Board governs runoff here, under a single regional MS4 (municipal separate storm sewer system) permit that covers 39 copermittee agencies across San Diego County, southern Orange County and southwestern Riverside County.

A regional permit of that size has a specific effect on private property. Because so many agencies share one permit, the expectations placed on commercial sites are unusually consistent from city to city, and the enforcement is correspondingly consistent. What satisfies Chula Vista satisfies Escondido.

What it asks of you is straightforward. Anything that leaves your site through a storm drain is a discharge, and you are expected to be able to show that your cleaning and drainage practices are designed to keep pollutants out of it. We contain and recover wash water rather than letting it run, capture solids at the inlet, and photograph and log every visit. Read what BMP (Best Management Practices), MS4 and NPDES (National Pollutant Discharge Elimination System) require of a private property owner.

Two forces do most of the damage here, and neither is dirt in the ordinary sense.

The first is salt. Coastal and near-coastal sites take continuous salt deposition on glass, aluminum and painted steel. It is corrosive, it holds moisture, and on curtain wall and storefront systems it works into the fixings.

The second is the marine layer. San Diego’s overcast mornings keep north and east elevations damp for hours after sunrise, which is exactly the condition algae and mildew need. That growth appears on shaded concrete, stucco and roof tile long before anything on the sunny side of the same building shows dirt at all.

• Salt film on glass, storefront framing and metal panel
• Algae and mildew on shaded elevations, walkways and tile roofs
• Canyon and construction dust carried in by Santa Ana conditions
• Irrigation mineral staining on hardscape and building bases

Biological growth is a chemistry problem. It is removed by soft washing, not by pressure, and pressure on tile or stucco simply drives water where it should not go.

• Corporate Campuses & Office Parks Research and office campuses through Sorrento Valley, UTC and Carlsbad
• Hotel & Resort Coastal hospitality where salt exposure and guest-facing standards set the schedule
• Commercial & Retail Property Centers and plazas across the county
• Hospital & Healthcare Entrances, canopies and ambulance bays cleaned without interrupting the facility
• Logistics & Distribution Otay Mesa and border-corridor facilities with heavy truck movement
• HOA & Multi-Residential Common areas, garages and walkways on a fixed annual program

Coverage runs from the North County coast through the inland valleys to the border.

• Why does the shaded side of our building look worse than the sunny side? Because it is biological growth rather than dirt. The marine layer keeps north and east elevations damp long enough each morning for algae and mildew to establish, and they will keep returning until the surface is treated rather than just rinsed.
• Does salt exposure really change the cleaning schedule? Yes. Within about three miles of the coast we typically recommend quarterly attention to glass and painted metal, because salt left in place corrodes fixings and etches glazing rather than simply looking untidy.
• Do the rules differ between cities in San Diego County? Very little, and that is the advantage of a regional permit. Thirty-nine agencies share one MS4 permit here, so the practices and the documentation that satisfy one city will satisfy the next.
• Can you service a campus that operates around the clock? Yes. Research and healthcare campuses are worked in sections on a rolling schedule, with routes and timing agreed in advance so no entrance or loading area is out of use during working hours.