What type of work requires a permit for a new septic system?
- Constructing a dwelling unit on undeveloped land requires a new OWTS.
- Constructing a dwelling unit on developed land may require a new OWTS.
- Constructing an accessory dwelling unit on developed land may require a new OWTS.
- Constructing a new or replacement septic system requires a septic permit.
What type of septic work requires a replacement permit?
Replacement of the septic tank; replacement of more than 25% of the dispersal system; or replacement of a pretreatment unit.
What type of septic work requires a repair permit?
- Replacement of 25% or less of the dispersal system.
- Replacement or repair of the leach line, whole or segment, within an existing trench.
- Repair of the pretreatment unit.
What septic work is permit exempt?
- Sanitary tees
- Effluent filters
- Diversion valves
- Distribution box
- Sewer line from house to septic tank
- Sewer line from tank to distribution box
- Solid sewer line connecting distribution boxes
What building permits trigger a septic review?
Building permits that require a set of plans.
What building permits do not trigger a septic review?
Septic review is not required for building permits that do not require sets of plans:
- Water heaters
- Electric service
- Electric repairs
- Interior wall covering
- Dry rot repair (greater than 40 linear feet)
- Deck repairs
What is the building permit septic review process?
Sonoma County Code requires the Well and Septic Section to review and clear building permit applications for structures that connect to an OWTS (new dwellings), or where a proposed alteration/modification imposes additional burdens upon existing systems (adding a bedroom or increasing the waste flow) or where property is being improved in excess of its capacity to absorb sewage effluent (additions, new square footage, or accessory structure physically impacting a system and/or replacement area(s)).
These types of building permits will be routed to the Well and Septic Section for their review and comments.
Building projects that add/increase wastewater will need to demonstrate or construct a code compliant system. Building projects that do not add or increase wastewater will need to demonstrate an existing OWTS. All building projects will be evaluated relative to their footprint and how it affects the current system and replacement reserve areas.
What type of building projects create an increase in wastewater flow?
Adding bedrooms or commercial processes involving increases in water use.
What land constraints are considered during the septic review process?
Land encumbrance includes paving or covering the land with structure(s), setbacks from wells, septic creeks, and steep or cut slopes. When reviewing your building permit application, staff would determine whether the proposal encumbers the parcel to the point that the replacement reserve septic area needs to be properly established.
Can I build an accessory dwelling unit without increasing septic capacity?
Maybe. If you increase the overall wastewater flow on the property, you’ll need to ensure that you have adequate septic capacity for this increase. This can be done by evaluating the capacity of an existing system or constructing a new system. Another approach is to offset the increase by reducing the number of bedrooms in the primary dwelling. Regardless, a septic tank is needed for the accessory dwelling.
What is a code compliant septic system?
A code compliant system meets the standards outlined in the OWTS Manual, or meets the intent of the standards by proposing mitigation measures that are equal to the standards. Code compliant does not mean that you need a new system or that you meet each and every standard. The County allows variances from the standards provided sufficient mitigation is provided.
How much will it cost if I need to replace my septic system?
Costs vary, but here are some estimates:
- $5,000 Replacement Tank
- $10,000-$15,000 Replacement Dispersal System
- $20,000 Standard System
- $70,000 ATU/UV Disinfection / Dispersal
Under the new regulations, how long will it take to have my septic permit reviewed and approved?