From Breitbart.com:

At least four Palestinians drowned in a tsunami of raw sewage on Tuesday when a water treatment reservoir burst, flooding a village in the northern Gaza Strip.

The deluge, triggered by the collapse of a septic system aid organisations had long warned was dangerously overburdened, submerged dozens of homes in the Bedouin farming village of Umm al-Nasr beneath a cesspool of foul-smelling effluent.

See also the BBC followup.