It's sad that people will not listen to a little common sense. Of course there are lots of rather not nice things one can do but that also tends to make for even worse neighbors.

If you got lemons, make lemonaid. If you got waterloged neighbors, maybe a pond? Of course, I love ponds so you might consider going with the ... flow, so to speak. Add a pond with some nice fish, water plants, and something like pampas grass or papyrus. Lovely water loving additions. I happen to like cat tails and I believe they grow like weeds in your area. Water features are all the rage in high end landscaping these days, and you will have a generous contribution to keep the level up.
Other possibilities. If there is an agency that does something about mosquito control, you could report them for causing standing water.
A generous rock mulch of say 2 inch river rock VERY deep so that the water runs through and the mosquitoes can not get to it.
Just a note. Watering that much may be helpful if you are trying to over seed a lawn with winter rye for a green lawn in winter. But once the grass is up, once a day is plenty.
Arthur the Date Palm Guy

If all else fails, a shotgun may work. ;)

chances are they are using a automatic timer and don't know how to change it (that's why they are acting defensively). might consider helping them make the adjustment (detemine the brand then download the manual). three times a day is about 9 times too much water.

There is a valve on the outside of the home where the vaccuum breaker is. Also, most heads are adjustable.

Just saying.....

Astilbe loves water, also "CAT TAILS", or you might try some water lilies.

I'm in Texas too, (N.Central), so with the drought we are in now it could be seen as a blessing that they are helping out with your water bill! I just paid my water bill, NOT PRETTY!!!

Hope the plant info helps

Monarda didyma (bee balm) loves to soak up water from moist soil. I've planted it under all my drippy water spigots. I started with one tiny plant (Gardenview Scarlet) last year and it's grown big enough to be divided into 9 plants this year. It bears pretty rose-red flowers and is beloved by bees, butterflies, and hummingbirds. The bumblebees are on it every day.

Mints are also great for wet spots, and also prolific spreaders. (Monarda is actually in the mint family.) I especially like apple or pineapple mints. Plant it there and you can also use it for cooking or teas. Incidentally, the bee balm can also bee used for teas--I've heard that the addition of bee balm is what makes a normal tea become "Earl Grey".

Good luck!

Isn't it "illegal" to put something on your neighbor's yard without permission? I'd ask nicely, then offer to adjust if ro them (I did both to a new neighbor, they responded well) and then I'd simply threaten to call the law.

The way our street is graded on one side of our property both yards come downward, making a little stream between the two yards. Since the builder didn't want to pull out the sod and regrade the put a drain in the middle. I have no idea what that costs since they did it (on our neighbors side) but might we worth look at least.