Can you put fencing around your garden? You said you were not allowed to fence in the front yard, but what if you just did the garden area? It may be that the rule reads not to fence the perimeter of the yard- I would look into it and know for sure. You may also try planting shrubs that will get fairly tall and wide. Deer do not like to be in an area they cannot see, or to feel hemmed in. Deer can jump height and they can jump width, but they cannot jump both, that is why shrubs are helpful. I did see one area where the landowner dug a ditch about 4ft wide and filled it with chuncky rocks and then planted a row of shrubs about 5 or 6 ft tall. You might think of something like that as a 'fence' if you can't fence at all. You may also consider surrounding the garden area with a plastic mesh like material. It is made to deter deer. I don't think that could be considered fencing because it is not a fence, and your primary reason for using it is to protect your garden.
I have heard of the sprinkler thing too but have not tried it myself. I have heard that the deer sometimes get used to it and realize it is harmless and if they are hungry enough they will ignore it after a while. Might have to move it around frequently or try adding something smelly to it they would not like like a scented laundry additive or such.
you could try getting a dog and using some invisible fence for it. I have heard that even a small dog will keep out deer and some dogs are handy to kill moles.
