I hope the following will be of use to anyone walking the Oxfordshire Way, either backpacking or just day walking. It isn't exhaustive by any means and only covers the Way between Bruern and Henley-on-Thames. There may be other water sources that I didn't see, of course. The sources that are streams or rivers should only be drunk after treating and/or filtering. I was walking the route FROM Henley.
Pishill church SU726898 - water tap inside gate.
Pyrton - stream at SU691963.
Stream - SP689004 steep bank down. May be muddy. Best to lower a container by cord.
Albury church SP655051- tap inside gate.
Waterstock - water tap at SP634054.
Islip - water tap at entrance to allotments. SP529137
Weston on the Green - water tap on wall of village hall SP531186.
Charlbury - water taps at rear of Baptist Church (SP356196) and the cemetery (SP355197).
Garage shop at Shipton-under-Wychwood - SP282182
Stream at SP334210 - shallow. Slight flow in drought conditions. Probably ok out of drought.
Stream at SP328207 - decent flow and deep. Will need to lower container with cord.
River Evenlode at SP301191. Decent flow. Cord required.
Community shop at Bledington - SP247266. There is a water tap which is probably accessible when the shop is shut.