Mobile Home Septic Tank Requirements

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A septic system will work for a mobile or site-built home.

When it comes to connecting a home to a septic system, a mobile home and a site-built home connect same way. The chief difference is that when a mobile home is moved, it cannot be towed across the tank, since the tank will collapse under the weight. Because of this fact, the location of the tank has to be planned out before a mobile home is installed.


Permit and Perc Test

A permit is needed for septic system installation. This is usually obtained through the county's building or health department. The county geologist runs a percolation test (commonly called a "perc test") to determine if the soil of the land will absorb water. Depending on the results of the test, the county may or may not issue a permit. If the county cannot issue a permit, then suggestions on alternative means of sewage disposal are usually available.


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Size of Tank

As part of the permit process, the geologist will design the septic system. The size of the tank is usually determined by the number of bedrooms in the house and the number of occupants. The more bedrooms and occupants, the bigger the tank. A common size for three bedrooms is a 1,000-gallon tank; this is a minimum, however. Your local county may have different criteria.


Size of Leach Field

A leach field (also called a drain field) is a vast array of perforated pipes placed below the surface of the ground to slowly "leach" the waste water into the ground. Based upon the results of the perc test, the geologist sizes up and designs the field accordingly.



Designing a system is only half the battle; the other half is installation. To ensure the system is installed correctly, most counties specify that the installers are licensed for septic system installation. An unethical installer, for example, might dig the leach field trenches only two feet deep to save time, when the geologist specified three-foot-deep trenches. The Environmental Protection Agency (EPA) states that an improperly installed system can contaminate well water, which is used for drinking.


Location of Tank

Because a mobile home cannot be towed across the tank, the geologist or planning engineer will want to see a plat before the building or health department issues a permit. A plat is a top view of the land, drawn to scale. On the plat, the location of the mobile home is depicted, along with the route the home will take to the location. The engineer then locates the tank on the plat away from the route taken.



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