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Sewer Inspections FAQs

Question

When do I need my first sewer inspection?

Answer

Your first inspection is required when trench digging is complete. We must see the bottom of the trench. This is called a trench inspection.

Question

Why are so many sewer inspections required?

Answer

Sewer inspections during the construction phase assure a quality connection. This protects the treatment plant from storm water infiltration. It also protects your property from sewage leaks.

Question

Why must I give 48 hour notice for a sewer inspection?

Answer

We schedule multiple inspections throughout the county every day. Because Sonoma County is so large, we try to schedule inspections for projects that are located near each other on the same day. With 48 hours notice we are able to inspect much more efficiently.

Question

My existing sewer pipes have worked fine for years. Why can't I keep using them?

Answer

Although they may seem to be working, older systems are seldom tightly sealed. This can allow storm water to enter the system which will cause problems at the treatment plant.

Question

Why can I use rubber couplings (Calder or Fernco couplings) for connecting my sewer pipes?

Answer

This type of connection is typically used for joining unlike pipes, such as iron pipe to plastic pipe.

Question

Why do I have to dig such a deep trench to connect my house to sewer?

Answer

The depth of cover required for plastic pipe is a minimum of 24". This depth helps to protect the pipe from damage. If you are using iron pipe the minimum cover depth is 18".

Question

Why am I required to install a backflow preventer? My neighbor didn't have to do this.

Answer

The purpose of the backflow preventer is to stop sewage from backing up in your home in the event that the main sewer line becomes blocked. Each sewer connection is unique. Your house may be at a slightly lower elevation than that of your neighbor.

Question

What type of material do I use for backfilling the trench?

Answer

This varies from one project to another. You must use #4 rock (pea gravel with fines) or other materials approved by PRMD.

Question

Do I have to hire a licensed contractor to connect my sewer?

Answer

A licensed contractor is required for any work in a public right of way. On private property, we recommend the use of a licensed contractor if the trench depth is over 5' or if a grease trap or monitoring manhole is required.

Although every effort is made to provide complete and accurate information on this website, users are advised to contact appropriate Permit Sonoma staff before making project decisions. This may involve contacting more than one section within Permit Sonoma(e.g. Building, Plan Check, Zoning, Well & Septic, etc.) since each section implements specific codes or ordinances which may affect your project.
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Permit and Resource Management Department County of Sonoma