Southern Surrey.
Tap TDS hovers around 200.
Pressure from mains unknown as the RO is not on my property so I can't really check it. The RO is fed from a standpipe that is linked to the mains via a property 100 yards away. Therefore, the pressure by the time it gets to my RO only hovers around 35 - 40 PSI. Although a Merlin is meant to have a minimum of 40 PSI, it manages to produce 30 - 40 litres per hour (depending on time of year) with the waste partially restricted for logistical reasons. As a sole trader, I find that sufficient. Before I restricted the waste, the Merlin gave around 006. After it's more like 016 once it settles down.