You shouldn't mulch citrus trees.
As for water, it sounds like you are giving it enough but the tree will tell you if it wants more by the leaves.

Get a bigggggggggggggggg rake and pull the mulch 16 feet BACK away from the tree in every direction.

Plant em if you got em.
Sam

Just fruits and Exotics recommends 1 inch per week of water with the first year being the most critical. They also recommend mulching under the canopy to help in keeping the weeds and grass at bay, except for a 1 foot circle around the trunk. University of Florida recommends keeping a 1 to 2 foot area around the trunk free of mulch. Lots of info available online from growers and Ag schools, some of it contradictory. I live on a sand dune, so I pray for rain and water when it doesn't come.

FWIW, you can successfully mulch citrus - as long as the mulch isn't excessively thick or piled against the trunk.

Mine are almost all mulched w/ oak leaves & much healthier than when they were not...

Here is a link that might be useful: EDIS Citrus Guide

a little more info about the mulch I use. It's something i picked up at a local farmer's market that was recommended specifically for citrus. It's wood chips and hay that has served as bedding for rabbits for several months, so it has nutrients in it. Now, why shouldn't i mulch citrus trees?

Bare earth under citrus is old-school dogma, IMPO - based on commercial practices(?)

My citrus are lightly mulched too and they are doing great. It's not thick at all though, just enough to keep the grass and weeds out from it.