Whether you need a water treatment recycling system depends on your business's size and the type of new construction or remodel.For new commercial buildings 10,000 sq ft or larger, graywater systems are required, and those over 50,000 sq ft must have dual plumbing for a potential graywater recycling system. Even if not mandated, installing dual plumbing in any new or remodeled building is encouraged to prepare for future recycled water use for irrigation or other applications.
When you might need a system
- New commercial construction (10,000+ sq ft): You will likely be required to install a graywater system for irrigation, according to a local ordinance (check city-specific rules).
- New commercial construction (50,000+ sq ft): You must install dual plumbing that allows for a graywater recycling system.
- Remodeling existing buildings: The "Ahwahnee Water Principles" suggest installing dual plumbing during remodels to prepare for the future use of recycled water for irrigation, toilet flushing, and commercial/industrial processes, even if it's not a strict requirement today.
- When it's not mandatory
- Existing businesses: Mandatory recycling is not required for existing sites in areas where recycled water infrastructure is not yet available.
- Small graywater systems: You may not need a permit for a very simple graywater system that collects water only from a clothes washer, as long as it doesn't require plumbing modifications or pumps, but it must still meet state and local design standards.
- Important considerations
- Local regulations: The requirements can vary. Check with Permit Sonoma and the Sonoma Water Agency for the most current and specific regulations that apply to your property.
- Dual plumbing: Installing dual plumbing (also called purple pipe) is a proactive measure to make it easier and cheaper to install a full recycling system in the future.
- Graywater limitations: Graywater can be used for subsurface irrigation, but it's generally not approved for use on root crops or the edible parts of food crops.
- Permits: Any graywater system that requires modification or plumbing work needs a construction permit from Permit Sonoma or the authorized permitting agency.