Sanitary lateral
Carries wastewater from toilets, sinks, showers and other fixtures toward the municipal wastewater sewer.
Storm lateral
May carry foundation drainage or other stormwater toward a municipal storm sewer, depending on the age and design of the property.
Why the difference matters
Valve suitability, code rules, the number of devices and rebate eligibility may differ. A camera inspection and plumbing assessment can help map the connections.
Questions
Can I install or service the valve myself?
Backwater-valve installation is regulated plumbing work and should be performed through the appropriate qualified and licensed contractor. Homeowner maintenance should follow the manufacturer instructions and local safety guidance.
How often should the valve be checked?
Follow the manufacturer instructions and local guidance. Some authorities recommend inspection every three months, while other programs recommend at least annual or pre-storm checks.
What if I cannot find the access?
Do not assume the valve is maintenance-free. A plumber or drainage contractor can help locate the device and determine whether the access has been covered or removed.