At the terminus of each trench is a leaching pool, built by digging a hole about three feet across and five feet deep.  It is filled with crushed stone or small rocks to the level of the trench piping.  Over it, before replacing the dirt, goes another piece of roofing paper.  Into these pools drain what water has not seeped away in flowing from the tank.

As can be seen from the foregoing description, the fermentation and bacterial action that takes place in a properly built septic tank system is automatic and needs no attention, although every second or third year it is advisable to remove the mud-like sediment from the tank.  Otherwise, the latter’s capacity gradually diminishes.

The steps involved in building such a system are so simple that, while the services of a plumber are advisable, it is possible for an intelligent handy man to do the work.  Be sure, however, that he realizes that each step is important and necessary.  We knew of one otherwise capable workman who calmly omitted the crushed stone and gravel in the tile trenches.  The system worked well for about four years.  Then, one warm and sticky day in July, it ceased to function.  A plumber demonstrated that the tiles were clogged with silt because the bed of crushed stone had been forgotten.  For a week the house was sewerless while the careless short cut was remedied.  The household had but two alternatives, take a vacation or go primitive.

However, if a properly installed system fails to work, the cause lies in what it has to digest.  Too much grease or too strong antiseptic solutions will reduce or prevent proper fermentation.  Waste grease should therefore go into the garbage can.  Also, strong doses of germ-killing solutions poured daily down sink-drains and toilets can put the hardiest septic tank out of action.  The remedy for such misguided sanitary efforts is simple.  Turn on all the faucets in the house and so flush the tank thoroughly.  Then pour down a toilet one or two pails of warm water in which a dozen cakes of yeast have been thoroughly dissolved.  The bacteria of the yeast will re-establish fermentation in the tank and all will be well if no further doses of disinfectants come along to interfere.

When one stops to consider, the septic tank is a remarkably simple and effective means of being rid of household wastes odorlessly and without contamination.  Of course, such a system should be placed as far as possible from a water source and the disposal fields should not be located in a low, damp ground.  The drier the soil, the better.  Incidentally, a lawn which turns brown during the dry weather of summer can frequently be kept green if watered by such a method.  The lines of the disposal pipes can be laid in practically any pattern desired.  Fan-shaped or with parallel laterals is a favorite one.  Here the branches should be so spaced that they are six feet apart.  This will give plenty of surrounding earth to absorb the moisture.