Before you build a septic system for your small house, the soil on your land parcel must pass a percolation test or soil analysis. The process of installing septic systems always follows the percolation test procedure and the results of test will determine how well the septic will function. It will also determine what type of a septic system you will need and the expenses that will be incurred as a result.
Depending upon your jurisdiction a percolation test or soil analysis is required when you submit your building plans to the planning board. You will want to check on the requirements for your jurisdiction.
You can perform your own unofficial percolation test to get an initial idea of the permeability of your soil. It is actually quite easy to dig your own percolation test hole with a post hole digger. Generally, you must make the hole at least three feet deep — but requirements differ according to jurisdiction.
The percolation test hole must be dug in the location where you plan on installing the septic system. As a general rule, when you fill the hole with water it should drain out within 20 minutes in most cases.
Once the soil has passed the soil analysis or percolation test you can then proceed to build the septic system. The septic design should reflect the need for space for drainage as well as a drainage system at an incline that allows the waste material to flow away from the house. Although this is typically a downward drainage, I have known instances where the soil did not pass the percolation test and it became necessary to install the drainage field above the house which was built on a hillside.
Although this is a rare instance, it can happen, and the result is having the waste material pumped up hill into the drainage field and from there it drains out. This is a tricky procedure which requires the installation of a tank alert in the basement to notify you if the uphill pump is not working properly. You want to be aware of this because it could result in an unexpected expense to your house septic budget.
Installing septic systems depend upon so many variables because it is important for the system to be designed so it is not running on overload. Variables include type of soil, number of bedrooms, as well as the number of fixtures and appliances in the house. You will want to discuss these issues with your septic system designer and any future plans for additions or renovations.
I ended up going with a conventional septic system because that was the easiest route to go at the time. Even a holding tank would have required a variance in my jurisdiction. But, I was lucky in that my land parcel had the type of soil that allows for a conventional system.
The one mistake I made in ordering my septic system was to order it for a 2-bedroom house. This precludes a future resident from officially adding another bedroom to the house. For example, if they decided to finish off the basement as a “den” with an adjoining bathroom, and then moved a bed in there after the final inspection, it would probably pass as a non-bedroom.
When you build a septic system for your small house, an accurate soil analysis or percolation test, and good judgment of usage, the septic will serve now and in the future, and consistent maintenance once the system is installed and established, are all factors that will keep your system headache free for many years.