Hi, it's time to install a new field and having read John Aldrich's (Septic Tank Yank) recommendations I'm a little torn over which route to go.
I installed Infiltrator brand graveless chambers about 8 years ago as per manufacturer's instructions. I'm in sandy/gravel soil with the water table at 30'. Fast perc. Two bedroom home and 120' of infiltrators in 2) 60' runs. No washing machine or shower goes to septic tank. I pump out the tank every two years. Soil around infiltrators is clean and dry and the biomat formed right against the infiltrators completely clogging them.

Is it likely that the exclusion of geotextile contributed to the formation of the biomat, or the exclusion of vents at the ends of the infiltrator runs?

I have two separate installers who are friends that I can hire to help me and one advocates the graveless chamber system (but insists on back filling around the chambers with stone), and the other swears by stone and pipe claiming that the biomat forms quickly with the chamber system.

Thoughts? Thanks, Daniel

We have two infiltrator chambers that have worked flawlessly for 15+ years. In our case they are uphill, driven by pumps. It sounds like ours have a heavier load than yours-our showers and laundry do drain into them.

Your install should have lasted longer than 8 years based on your description. You have identified some substrate and water table issues, but there are more. The reason your two advisors disagree is that there are more variables than any of us are considering. The manufacturer is great with questions like yours. [www.infiltratorwater.com]



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