I got up for a glass of water in the wee small hours of last night. When I switched on the tap, it made a horrendous noise, and the water came coughing and spluttering out, and was a cloudy white colour. This morning it was fine again. Any ideas?
Nothing to worry about, it sounds like an air-lock.
This sometimes happens, the cloudy white cloour is disolved oxygen and should clear if you let it stand a while.
The water in the pipe is under pressure, and the oxygen T'bird mentions is released in the same way as fizz when you open a bottle or can of lemonade or beer. It's just that the oxygen bubbles are teensy-weensy, giving the milky appearance to the water.