We bought this property at the end of July, '01 "as is", with no power, water, gas, or sewer service provided. With no township sewer on this stretch of road available, so we had to install in on-site sewage disposal system. Back in the old days, this might have been called a "cess pool", or "septic tank", just a big holding tank where all the waste collected. This tank would occasionally be emptied, and the contents disposed of off-site.|
These days, an onsite disposal system consists of a a big underground tank (1500 gallons, in our case), into which waste is collected and broken down by naturally occuring bacteria. In the tank, this decomposed waste separates into "sludge", "scum", and a more or less clear liquid. The sludge falls to the bottom of the tank, and the scum floats to the top. Both of these need to be periodically emptied (every two or three years). The liquid, however, drains from the tank into a drain field, where it is filtered back into the soil and further decomposition occurs.
An onsite system can cost anywhere from about $3,000 to $20,000, with the cost difference depending on the type of soil. If the soil drains too fast, the effluent doesn't have time to decompose, and sewage can end up contaminating the groundwater. If the soil drains too slowly, the system can get overloaded & back up.
Two tests are performed, a soil test and a percolation test. The soil test consists of a couple of 7' deep trenches dug, and the soil examined by the local sewer enforement officer. In our case, we also hired a geologist who often works with the township to lend his expertise. This visual test can immediately rule out certain soil types, but if the soil looks promising, then the percolation (or "perc") test is performed. Here, a few small holes are dug and filled with water, and the rate of drainage is measured.
If this percolation rate falls within a certain acceptable range, then a standard in-ground system can be used. If the flow falls somewhat outside this range, then then a "sand mound" system has to be built - this is a system that essentially creates the correct percolation rate by building up a mound that the effluent will pass through.
The sand mounds can be expensive to build - that's the high end of the cost scale. We were lucky enough to have soil suitable for a shallow, two trench system, which only set us back about $3,200. This, as you can imagine, was a big relief!
Alas, there are no good pictures of the septic construction. Apparently, I don't know how to rewind the film in the camera, and ended up ripping it. We recovered a few pictures from the roll, but those valuable photos of Sam Leh & sons expertly constructing our little sewage treatment center didn't make it.