8’ deep koi pond. Water ingress

Can it be glassed with this water getting in? Yes but that’s work for others not me these days, been there done that. Get some Sika 4a in there.

[@DavidScobie]

Would coating the back side of the blocks in some type of water repellent bitumen product not form a barrier to keep water from seeping through once the blocks have been laid and the backfill has been packed in?

[@graemeross6970]

Is tanking slurry any use or would it need to be drier for application?