Are there drinking water fountains airside at Birmingham International Airport (UK)?
there are water fountains in our International Pier to fill up. Hope that helps! #bhx
BHM airside: https://youtu.be/-LOzNRZE5A0?t=3m43s the fountain is well visible on the right hand side. (If you rewind to 3m28s you will see it's the bathroom area). As you can see this is gate A5.
IMO "after security" is airside because you do not pass security when landing. If I am wrong, well, others can research landside but I suspect it'll be much harder to find and might require asking on Twitter.
There is one by gate 47, next to the sign. It could not be less obvious and is not signposted or marked on any map. Customer service staff seem unaware of its existence. There is none in any of the main toilets and I couldn't find one in the Flybe/Ryanair hub.