Our septic tank was put in by the previous owner for the original house that burned in the Cedar Fire. It is a plastic tank with a leach field of 300 ft. Because our new house was smaller in square ft than the original, we were able to use the existing tank that was not damaged by the fire.

In a septic tank, basically the waste water flows from the house into one end of the tank where solids sink and are hopefully broken down by bacteria (though not completely). The water that flows out of the tank is high in nitrogen and phosphorus (fertilizer) and is spread out through the leach field were it soaks into the soil. Yes, often you can tell where the leach field is because the grass actually will be greener in those areas.

Maintenance - The septic tank operates by gravity so other than the fluids, you have no moving parts. Eventually, the sludge that doesn�t break down fills the tanks to a point when it must be pumped out by a septic tank pumping service. In rural areas these services are easy to find and sometimes they�re the biggest businesses in the area.
When do you know when to have your septic tank pumped? Most services can calculate a service schedule when given the details of your system. Many people have the service come out on regular intervals whether the tank is full or not just as a routine. The other method for knowing it�s time to be pumped is when raw sewage flows into the leach lines. Yep, you smell it. Though this method is somewhat comical and frankly used by most people I know, it�s not recommended. The leech lines can fill with solids that restrict flow and then require additional maintenance.

Tips � Usually, when you buy a house in the country, the health department requires that the tank be exposed for inspection. Take that time to note, photograph and mark where the lids to the tank are. Yes, the pumping services are pretty good at finding them but you can really save time and effort by knowing exactly where they are. I have my tanks marked with a exposed piece of PVC pipe that is driven in directly over the tank lids.

Know where your leach field lays. We avoid planting trees with invasive roots in the leach field area and many people reserve that area for small gardens.  It's also useful to know where the pipes are when you're running around with a back-hoe digging lines for new power lines or water.

New Construction - Building codes for septic tanks vary all over the country and in San Diego County you have to go through several steps before receiving the permit. A leech test is required to determine if the proposed spot will be able to absorb the fluids that come out of the tank. Basically you dig a hole, fill it with water and monitor how long it takes for the water to sink into the ground. The health department will have to come out at least twice. Once to inspect the site and once to inspect the installation.