Posted: 03/08/2016 at 17:45
we have field maple, hawthorn, Cotoneaster lacteus and small yews (to be kept small) very close to ours. There are willows and a privet hedge within rooting distance, they've been there since 1960 and haven't caused problems yet. The onbe that has pushed roots between bricks into a manhole is the shallow rooted Catalpa bignonioides. A lot will depend on the state of your system, roots in the soakaway are probably not a big deal but if you have an old crumbling brick tank that might be bad news.
Our tank has always been known as the sceptic tank. Some people are a little septic about its efficiency but we know it works just fine