no mate, it`s not easier!

Fit an outside tap in 15 minutes flat. The self fitting ones from B+Q are about £15.00 and easy to fit.
Put the RO/DI in shed, a water butt or maybe 2, outside shed.
Attach one end of hose to tap, the other end to the start of your filter system, turn on the tap and let the water filter through your filter system finally coming out the end hose into your water butt(s).
A few hours and you have 400 litres of pure water.