Mohammed al-Khatib fears for his life every time he gets behind the wheel. In wartime, providing drinking water to homes and schools in Gaza means dicing with death.

At 23, Khatib is a veteran of two previous wars between Hamas and Israel, in 2008 and 2012, but nothing prepared him for the bombings, shredded nerves and death toll this time around.

"When I'm driving, I always feel frightened, upset and nervous," he tells AFP in the small warehouse where he loads up his truck with drinking water, as Israeli air strikes boom in the distance.

It's an essential job in Gaza, where at least 90 percent of municipal running water is not fit to drink and war damage means that for many people the only water comes from private vendors or desalination plants.

But at his boss Hossam Huneif's desalination plant, down a sandy track in Gaza City, Khatib is one of the few drivers who turn up. Many of the regulars have stayed away since war broke out in July.

Khatib says he is exhausted by over-working, and lack of security, fuel and electricity. Then there are the horrors he has encountered.

"Perhaps I'll go to fill a house with water and find that house has been targeted by an Israeli air strike.

"For example, the Mata family -- I always filled their tank, then one day we went and their house wasn't there anymore. It was bombed."

Three of his friends have been killed and others have been injured. At home his family of eight has swollen to 30, as they welcome in refugees escaping the worst fighting in eastern Gaza.

"Mohammed has a brave heart," smiles Huneif, the plant owner.

Pointing at another driver who has just sauntered into the warehouse, he adds: "when he hears a bomb going off, he stays at home."

"If there is bombing after 3 pm, his wife calls him all the time saying 'come home,' 'come home'," Huneif chuckles.

"There's another driver who's only been to work one day since the war started. His family locked the door and said you can't work!"

Huneif owns the plant, a smart title for the small warehouse on a corner block where donkey carts rumble past.

Trucks are parked around the corner. In the morning, they fill up with water and set off to supply schools and homes across north and central Gaza, navigating craters and rumbling past bombed-out wrecks.

The charity Oxfam estimates at least 600,000 people -- a third of Gaza's 1.8 million population -- are without running water.

Many others get running water as little as one or two hours every two days, such as in the badly destroyed neighbourhood of Shejaiya, and repairs have been on hold since air strikes resumed.

- 'Fear. Death. That's what I feel' -

Before the war Huneif was fending off growing competition from other desalination plants.

In wartime, his 24-year-old son Mahmud, fresh out of university and an IT specialist, has had to take on shifts to replace drivers too nervous to work.

"At the beginning of the war, I didn't have a problem distributing water but after the tanks and soldiers came in and people evacuated to the centre I faced many difficulties," Mahmud says.

"People would stop the truck in the middle of the street, saying 'please, my child doesn't have water to drink,' and people would climb onto of the vehicle in their rush to get water," he adds.

Wearing cut-off green trousers and with gelled hair, he fishes out his smart phone to show a short video of the incident that perhaps scared him the most.

One day when he was handing out water, there was an air strike right in the street in front of him. People fled the truck in panic as ambulances, sirens wailing, rushed to the spot.

The jumpy footage shows paramedics pulling a blanket over a dead body in the road. But it wasn't his only close shave.

"Fear. Death. That's what I feel," he says.

Then there was the time he took water to a regular customer and the neighbouring house was bombed.

Mahmud says he happened to be in the next street when a series of Israeli bombs targeted Hamas's military commander Mohammed Deif, flattening a building and killing Deif's wife and two children.

But it's not safe back at the warehouse either.

"Yesterday open land was bombed just 100 metres (yards) from here," says his father. "But we have to keep working. This is a humanitarian job. It's not just a private company to earn money."