Septic system maintenance

When we first moved into our house at Nanango we thought we should probably get the septic pumped out, this went on the list of things we should do and quickly ended up near the end as we found more and more urgent jobs that required our attention.  Finally, 18 months later, with the evaporation trench getting a bit soggy, we decided it REALLY was time to get it pumped out and booked in a contractor.

a typical septic arrangement

Septic systems come in a few different shapes and sizes, ours is a large underground plastic tank, which all our waste water flows into.  The solids are supposed to sink and the liquid drains out of an opening near the top (but underground) and into a large evaporation trench (attractively located in our house yard!).  The evaporation trench should be a gravel-lined shallow pit, with grass etc growing on top, in which the pipes branch out so that the water can spread out and evaporate (also called the leach field).  Its pretty hard to tell whether or not its working as designed, and according to this report, many systems are not working because people don't know how to maintain them.

The "suck-truck" operator was very knowledgeable on the subject and gave us a few tips.  He said that the tank should be sucked out about every 3 years or so to remove the accumulated solids, this depends on the size of the tank and the number of people using it.  If the solids build up to the top of the tank and start to be transported into the evaporation trench it will eventually block up and you will have to dig up the whole thing and start again.  Not to mention the potential for pathogens to accumulate near the surface of the trench.

He also told us not to use any chlorine.  This will just kill the microbes that are working to break down the sludge and it will have to by pumped out more often. Some toilet cleaning products claim to be "septic safe" while still containing chlorine, so he recommended to use natural cleaning products (bicarb soda and vinegar) instead.  Just another reason to ditch the chemicals!  The only bleach we use is in cleaning the beer fermenters, so that is now being tipped outside instead of down the drain.

So if you have a septic system that hasn't been pumped out for a while, its probably worth getting a suck-truck out to do the job, then at least you know you're not going to block up your trench and have expensive repair work instead!  The other advantage for us is that most of our grey water goes to the garden instead of filling up the septic tank.

Do you have a septic tank?  Any tips for maintaining it?