Just had a sewage consultant in. He actually recommends a simple septic system rather than a complicated sewage treatment system. Less moving parts to fail plus being on a hill with sandy soil, we wouldn’t be contaminating the water table. I was intrigued plus it saves us some cash. That does mean we can’t do a grey water system as we need the water for the septic system. That would have been the same for a treatment system though. Pity though we’re still going for a rainwater collection system that we’ll run the loos off of. Nice to have something fun outside of work to engage the brain.