In November 2007 work started to connect me to the public sewer. I'm having a really deep sewer so quite a serious excavation was needed. I assumed this would result in more ground water which would flow down the pea gravel bedding the sewer pipe but I wasn't ready for what happened next. 15,000 litres per day flowed into my basement. There was no way the little 25 watt pump would cope so I got a 500 watt mains powered pump. Knowing nothing about ground water I assumed this would stop after a couple of days once locally saturated rock had drained but it didn't. The photo above shows my basement the day after the pump failed. 18,000 litres of water. I was having real trouble dealing with this for a week and then the cause was discovered. A split water main about 10m away. The split could have been caused or enlarged by vibrations during the sewer excavation work but more likely it was a really old water main. Once reported, the water company acted very quickly fixing it the following night. I am hoping to use ground water to flush the toilet and keep the house cool during the summer (regulations etc. permitting) but I no longer know how much ground water to expect. The original ground water back in May 2006 could have been the start of this mains leak.