Your Septic System Specialist

Serving Nevada County
(530) 273-2964
P.O. Box 975
Grass Valley, CA 95945


Our Family of Companies

Your Neighborhood Plumber, serving Nevada County

Navo & Sons, Inc
Your Septic & Leachfield experts in Nevada County

All-Sierra Septic
Your Septic & Leachfield experts in Placer County


Perc & Mantle

What is a Perc and Mantle?


Soil test pits or soil mantles are excavations done with a backhoe to verify effective soil depth. Effective soil is considered soil that will treat or filter sewage. For a standard sewage disposal system (in our counties) a minimum 6 feet of effective soil is required, 4 feet of effective soil below the trench bottom. The standard trench depth is 24-inches.


Percolation test are used to determine how fast or slow water will filter through the soil. A perc hole is dug to the anticipated trench bottom or to the limiting horizon. The hole is pre-soaked to simulate winter time or wet weather conditions. Readings of how quickly water leaves this hole are taken the following day. These reading are then averaged to calculate your average percolation rate.

Process To Install The Average Septic System in Placer County
Time Completed Description Anticipated Cost
1-3 days

Create a check made out to
Placer County Environmental Health Dept.
(P.C.E.H.D) and then go to PCEH to pay/apply for the Perc & Mantle
(P&M) (see below)


1-5 weeks


To schedule the P&M (after paying the County) contact US





5-7 days

Because we are one stop shop we provide the backhoe,
operator, designer for 2 mantles and 3 perc test -
(A Standard P & M).The designer will complete
the P & M paperwork.

The County supervises Navo & Sons (ie designer,
backhoe, and operator) performingthe P& M Please note:
It is recommended to have owners or owners representative present on this first day



1-2 weeks

If a design is needed: The designer will quote a firm price
to perform the specific design and time to complete said design

Please note: Upon approval and completion of the design
we can provide a firm installation cost for the system


1-6 weeks

Once the design is completed, the 2 design
originals will need to be taken to P.C.E.H.D. to
apply for the installation permit of system


1-3 weeks Once a permit is issued we can usually start installing the system. Depends on the system