If water leaks from sewer continuously then you have a chance for increasing the rate of settlement and soil certainly collapsed due to water infiltration into soils. But, this kind phenomenon is applicable to organic soils with high degree of dispersion..
What if the water leaks from sewer/ water pipeline is non-continuous (cyclic)? Means if water is flowing for an hour and then stops for 30 mins and than flow for 1 hour and stops for 30 min and cycle continuous..
In non-continuous (cyclic) leakage is a dangerous phenomenon of contamination, due to variation of water pressure, where the polluted water enters the water pipeline system. In continuous leakage this process not happen, because of no inlet-outlet cycling. In continuous leakage the collapse may not happen due to stable pressure or latter happen, but in cyclic leakage the collapse rapidly happen.