1. unless your water is free, why not call a plumber in the morning?
i'll guess the leak is causing the mushy area. if you have winter and a
crawl space, you may need to add an automatic thermostat anti-freeze
pipe wrap heater after the plumber's repair. ask him.

2. if you use a washing machine double female and a white drinking
water rv hose to hook up to the neighbor's house hose cock to yours,
would that help to pinpoint the leak?