Opposite my bookshop is a fire hydrant and recently a chap appeared opened the inspection cover put a metal rod down the hole and listened to the other end for the sound of running water, soon it became apparent that all was not well. The inevitable roadworks ensued.
Next time it rained heavily the road outside the shop became a lake so I called KCC and they sent the chaps with gully emptier to clear the drains who discovered that the chaps who repaired the fire hydrant had removed a section of the pipe for the drains.
Now when the water goes into the drains on the hill opposite the shop it comes out of the drain at the bottom of the hill flooding the road.
My main point here is that it is workers of this calibre repairing pipes at commercial operations on the drinking water aquifer that can lead to problems.
The picture shows water going in one drain and coming out the other.