Perc & Mantle

What is a Perc and Mantle?

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.

Perc

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.

What is an O.S.S.E.

Before applying for a new septic system, it is necessary to have a valid soils testing (On Site Soils Evaluation - OSSE) done. An OSSE includes soil tests that determine the effectiveness of soil to filter sewage through leach lines, as well as observations of required setbacks, constraints and possibilities for an individual, “on-site” septic system. The Soils Evaluation Report produced by the consultant (Navo) of the particular site tested on a parcel is reviewed and evaluated by an Environmental Health Specialist who generates a findings report. An OSSE must be conducted by a Nevada County approved Soil Testing Consultant (navo). Soils Evaluation Reports are valid for 3 years. Consultant (Navo) re-certification is required for any reports exceeding 3 years.

Quick steps to apply for an OSSE/ Perc & Mantle

1) Hire a Nevada County Approved Soils Testing Consultant (Navo)

2) Your Consultant (navo) will Apply for the OSSE using some forms you will fill out

3) Consultant (Navo) schedules an OSSE (see below)

4) Consultant (Navo), Backhoe operator (Typically Navo) and Nevada County Specialist meet on site for soils testing

5) Consultant (navo) submits Soils Evaluation Report to Nevada County

6) Nevada County Specialist generates Findings Report to approve what type of septic system to install

7) AFTER This a design can be created by your Consultant (Navo) to apply for the permit and get an install estimate

8) You may then proceed to apply for a Septic Permit