One thing I find most attractive hunting water vs land is precisely the lack of targets.
A bit more relaxing, and when you do get a signal it tends chime out like a bell and really gets your attention. I have a habit if singing while detecting in water, a song will come to mind, say Light My Fire, and I'll keep singing it over and over, don't know why.
I kinda go into a daze, but when that target sings out in my ears I snap right to it, and often it is a ring. It is exiting and even exhilarating tracking it down, sometimes you snag it on the 1st scoop, others I have spent 20 minutes at, some are never recovered though the signal is good. I'd say 90% of targets I get within 3 scoops.
Obviously, there will be a fair share of trash/clad in the water, but no where near the proportion on land, and for an obvious reason - People simply don't take out into the water the things they do on land nearly as much, most often because they are in swimming suits and don't have pockets, and the only ones who take out beer/pop out in the water [and hence tabs] are the ones who float around and drink, not a very large % of swimmers.
There are exceptions of course, notable and sometimes notorious water hunter ScubaDetector took me to a spot on Anchor Bay here in MI late last summer only accessible by boat, right off of Selfridge ANGB. He told me in advance that it was littered by spent shell casings used in air to ground practice back in the day , and he was right. Talk about ringing like a bell, every one of them sounded like a 50g gold ring. It is also a known gathering spot for boat partiers and he had found gold there.
didn't take me long to get hugely frustrated with the plethora of trash, plus the bottom was not sand but rather pure stinky gray muck that resisted every effort to sift with a scoop - No singing at that spot ! I brought along a floating sand sifter and I had to mash the muck into the sifter like a cheese grater, not enjoyable so we moved on to another location after a couple hours.
But in general, most water detecting will be nothing like this and is enjoyable and relaxing.