I could use some snails like that, was just out front today with a broom cleaning algae out of my waterfall. Actually slipped and fell and sat down hard in the water, not my best move. Luckily only deep enough to get the seat of my shorts wet, thought I'd lost my cell phone, though. Duh, working in and around water, put your cell phone in a safe place.....

Never seen one around this way (Westminster) either! I did, however, see some tremendously large worms slip back into the soil after the hard rain we had today. The rain flattened my new very tiny Gourmet Popcorn rose so I went to inspect it and saw the humongous worms.

European Brown Snail?
https://en.m.wikipedia.org/wiki/Cornu_aspersum
Steve