Engineering Question
What Is a Sanitary Waste System?
A sanitary waste system carries wastewater from fixtures through waste and vent piping to the building sewer and public or private treatment system.
Reviewed by
Michael K. Frempong, PE, LEED AP BD+C
President & Principal Engineer, BEED Engineering
Michael is a professional engineer and LEED AP BD+C accredited professional with more than 20 years of consulting engineering experience. He leads BEED Engineering's mechanical, electrical, and plumbing design work for commercial, healthcare, laboratory, education, industrial, and other building projects throughout Central Florida and the Treasure Coast.
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A sanitary waste system collects wastewater from fixtures such as sinks, toilets, and floor drains and conveys it to the building sewer. Vent piping protects trap seals and allows the system to drain. The design must size pipes, provide cleanouts, and coordinate stacks with architecture and structure.
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What the system does
A sanitary waste system moves wastewater out of the building. It is not storm drainage and it is not domestic water.
Typical path:
Fixture → trap → waste piping → stacks and building drain → sewer
Vent piping connects to that network so traps keep their water seal.
Main components
- Fixtures and traps
- Horizontal waste piping
- Vertical stacks
- Vents and vent terminals
- Cleanouts
- Building drain and sewer connection
- Interceptors when the occupancy requires them (grease, oil, solids)
See plumbing engineering for related systems.
Design issues
- Fixture-unit loading
- Slope and available ceiling depth
- Stack location versus architectural cores
- Grease and specialty waste
- Coordination with domestic water heater rooms and risers
When to involve an engineer
Involve an engineer when adding restrooms, changing occupancy, installing a commercial kitchen, or replacing a failed underground building drain. Existing buildings in Brevard County often have limited stack capacity.
Common Questions
Is sanitary the same as storm drainage?
No. Sanitary carries wastewater from fixtures. Storm carries rainwater from roofs and site drains. Combining them is generally not allowed in modern commercial design.
Why do vents matter?
Vents protect trap seals from siphoning and allow air into the system so waste can flow.
Filed under Plumbing Engineering
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Related Questions
What Is Plumbing Engineering?
Plumbing engineering is the design of domestic water, sanitary waste, storm drainage, and specialty piping systems for buildings.
What Is Stormwater Drainage?
Building stormwater drainage collects rain from roofs and area drains and conveys it to the storm sewer or an approved point of discharge.
What Is Commercial Domestic Water Design?
Commercial domestic water design sizes cold and hot water supply, heaters, pumping, and backflow protection for building fixtures and equipment.
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BEED Engineering is based in Palm Bay and serves building projects throughout Brevard County, the Treasure Coast, Port St. Lucie, Orlando, and surrounding areas.
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