Sounds like this guy needs a new plumber 
Heh Ray you might check with your insurance carrier, mine will cover theft of track in backyard maybe your policy will cover damage done to yours from neighbors problem!!!Might check it out. Time is money and money is time! The Regal
Large or small leak, its water seepage on a hillside lot, thats the real issue and why something like this should never be left alone.
Luckily it was a relatively easy leak to find, like I said luckily it wasnt a cracked pool seeping into the soil, the situation I mentioned was just that, a hairline crack at the bottom of a swimming pool in a backyard uphill from a home like Rayâs. The pool owner thought he was losing water to summer evaporation, but the water was slowly seeping into the soil under the pool saturating the ground, it ventually saturated the ground under the pool which finally reached a plane of weakness in the soil and the backyard, 1/2 the pool and all the water ended up in the downhill homes living room! Unbeleivably messy and ugly.
Thing is if your regularly watering the hillside youâd never notice if its overly moist or not. Rays desert layout immediatly allowed the warning signs to show. So hopefully now that its fixedâŚfingers crossed 
When I moved into my Dadâs home, I discovered that the 50 year old galvanized pipes that we installed when I was a kid had finally rusted through. It leaked through the block wall in the basement. Luckily, I caught it in time. I had been gone over the weekend. Another day, andâŚ
Fortunately, we installed cutoff valves against just such an occurrence.