I am looking at buying a piece of raw land. What do I need to do and what is my first step?

We recommend that you first inspect the site with a private septic systems consultant. Qualified companies and individuals who can perform this service can be found by checking local telephone directories or the Internet.  The consultant you select should be familiar with Marin County codes and requirements.  The consultant should be able to give you at least a rough idea whether or not your plans are feasible. When you are ready to proceed, a consultant can help you apply to Marin County for a site review and percolation tests.

I am developing a raw piece of land. Can I get my septic permit before my building permit? Can I get my septic permit and my building permit at the same time?

Yes, you may obtain a septic system construction permit prior to the issuance of a building permit. However, the septic system permit will not become valid until the building permit is issued.

I am thinking of buying a house that is on septic but there are no septic records. What do I do? Can I remodel?

Sometimes records are available through other sources, such as prior owners or the Building Inspection Division. Under certain circumstances, and with a satisfactory septic system evaluation, we may be able to consider the system to have the rights and privileges associated with a Class III permitted system. See or contact EHS office for details.

How do I know the class of  my system?

Generally speaking, a recently installed septic system which complies with all current Code requirements will be a Class I system.

Sometimes, due to site conditions, soil depths, setback problems and other reasons it may not be possible to comply with all the regulations in one or more respects. If every effort was made to comply with current Code, we will probably regard the system as a Class II. This type of system is also referred to as a system which complies with the Class II Repair standards.

A Class III system is one which was given a permit by the County under prior Marin County Code (prior to 1984). Note that most, if not all, of these do not meet current septic system regulations.

Class IV covers two categories of septic system; cesspools -   (these are no longer permitted), or other existing septic systems for which no documented records are available.

How long does it take to get a septic system permit?

That depends on our current workload, staff availability and the complexity of your project. Summer and Fall are the busiest times of the year. Once a design is submitted to us with all fees paid, we try to respond in no more than 30 days. Contact EHS staff for a current time estimate.

How long are perc tests good for?

Perc tests performed under current regulations and witnessed and documented by EHS may be used until the current percolation regulations are changed, or modified.

If the property percs OK will I be guaranteed it can be permitted?

Not necessarily.  Due to other factors such as site conditions, soil depths, setback problems and other reasons it may not be possible to comply with the Code in one or more respects to allow the issuance of a septic permit.

My system is a Class III and has a redwood tank and I want to do some remodeling. Will I have to replace the tank? If I have to replace the tank, should I have the system evaluated first?

Yes, you will need to replace the septic tank and apply for a permit with appropriate fee. It must be constructed of approved materials, either concrete or fiberglass. A septic evaluation would be required at the least for any remodel. A hydraulic load test is required as part of the permit conditions for tank replacement.

How do I calculate the percentage of remodel I am doing when doing an interior remodeling only and not adding any square footage? For example, I want to remodel my bathroom and I will only be moving the shower and tub, putting in a new vanity and cabinets.

Any area that is being remodeled will be computed and divided by the existing square footage. Measure existing permitted habitable space including closets and bathrooms. The measurements should be taken wall-to-wall. Check County Building for further information.

Why does Environmental Health care that I am doing interior remodeling? If I am not adding square footage, or a bedroom, why does it matter to EHS when I am just trying to upgrade an aging house to modern standards?

County Code requires EHS to sign off on building permits prior to the permit being issued. EHS used to perform routine inspections of septic systems. Now, the only time we get to have the system evaluated to ensure that it is functioning properly is when the house is going to be remodeled or added to. It is a trade-off between routine inspections of your property or the occasional septic evaluation.  Homeowners also are personally liable for malfunctioning onsite systems. Onsite systems must be properly operated and maintained to protect groundwater and other drinking water sources, as well as the health of family and neighbors.

What kinds of remodeling can I do to my house that will not require a septic evaluation?

None. Each building permit application received will potentially require a septic evaluation.

I had an evaluation of my septic system done by a REHS or Civil Engineer when I purchased the property over a year ago. Will it still be valid?

We accept septic evaluations done within a year prepared by a qualified professional, a Registered Environmental Specialist or Civil Engineer. All others will not be considered.

Who can conduct an inspection of my septic system for a minor remodel?

An inspection can be conducted by a County-registered Septic System Inspector, a State Licensed Contractor (C-42), a Registered Environmental Specialist, or Registered Civil Engineer.

Can my house be condemned if I cannot repair my system to meet current code?

Our staff will make every effort to accommodate septic system repairs. These repairs are tailored to the specific lot and residence. Because of the many factors involved, we recommend that you contact one of our Land Use inspectors for advise on your particular situation.

I am looking at an approved subdivision.  Will I have to do more percolation tests for that lot?

Perhaps. The regulations permit subdivisions to be approved with a minimum of one soil profile hole and three percolation tests on each lot. To actually receive a permit to build an individual septic system, a total of two profile holes and six percolation tests per lot are required. You may have to look to install one more profile holes and three additional percolation tests. However, many developers initially perform the six percolation tests and two soil profile holes. In this case you may not have to do additional testing.

Does Environmental Health Services inspect the septic system before I purchase the property?

No. It is recommended that the individual buyer have the septic system evaluated by a qualified professional, either a  registered environmental health specialist or registered civil engineer.

Can I renew my permit?

Yes. Marin County Code Chapter 18.06.080 provides for a one year permit to construct and operate an individual sewage disposal system. This permit is renewable for one additional year only. After that a new application, plans and fees will be required.

What is Graywater?

Graywater is untreated household waste water which has not come into contact with toilet waste. Graywater includes used water from bathtubs, showers, bathroom wash basins, and water from clothes washing machines and laundry tubs. It does not include waste water from kitchen sinks, dishwashers or laundry water from soiled diapers.

What is an Alternative System?

Where the site conditions do not lend themselves to installing a standard type of system, there are alternatives.

For example, if ground water or percolation rates are unsuitable, it may be possible to install what is called a "mound" system. In a mound system, a suitable soil is placed above the unsuitable soil. A conventional system is then installed in the mound. There are some additional requirements for this type of design.