Deir Al-Balah, 15 August

After waking early to stand in line for an hour under the August heat, Rana Odeh returns to her tent with her jug of murky water. She wipes the sweat from her brow and strategises how much to portion out to her two small children. From its colour alone, she knows full well it's likely contaminated.

Thirst supersedes the fear of illness.

She fills small bottles for her son and daughter and pours a sip into a teacup for herself. What's left she adds to a jerrycan for later.

“We are forced to give it to our children because we have no alternative,” Odeh, who was driven from her home in Khan Younis, said of the water. “It causes diseases for us and our children.”

Such scenes have become the grim routine in Muwasi, a sprawling displacement camp in central Gaza where hundreds of thousands endure scorching summer heat. Sweat-soaked and dust-covered, parents and children chase down water trucks that come every two or three days, filling bottles, canisters and buckets and then hauling them home, sometimes on donkey-drawn carts.

Each drop is rationed for drinking, cooking, cleaning or washing. Some reuse what they can and save a couple of cloudy inches in their jerrycans for whatever tomorrow brings — or doesn't.

When water fails to arrive, Odeh said, she and her son fill bottles from the sea.

Over the 22 months since Israel launched its offensive, Gaza's water access has been progressively strained. Limits on fuel imports and electricity have hampered the operation of desalination plants while infrastructure bottlenecks and pipeline damage choked delivery to a dribble.

Gaza's aquifers became polluted by sewage and the wreckage of bombed buildings. Wells are mostly inaccessible or destroyed, aid groups and the local utility say.

Meanwhile, the water crisis has helped fuel the rampant spread of disease, on top of Gaza's rising starvation. UNRWA — the UN agency for Palestinian refugees — said Thursday that its health centres now see an average 10,300 patients a week with infectious diseases, mostly diarrhea from contaminated water.

Efforts to ease the water shortage are in motion, but for many the prospect is still overshadowed by the risk of what may unfold before new supply comes.

And the thirst is only growing as a heat wave bears down, with humidity and temperatures in Gaza soaring on Friday to 35 degrees Celsius.

Searing heat and sullied water

Mahmoud al-Dibs, a father displaced from Gaza City to Muwasi, dumped water over his head from a flimsy plastic bag — one of the vessels used to carry water in the camps.

“Outside the tents it is hot and inside the tents it is hot, so we are forced to drink this water wherever we go,” he said.

Al-Dibs was among many who told The Associated Press they knowingly drink non-potable water.

The few people still possessing rooftop tanks can't muster enough water to clean them, so what flows from their taps is yellow and unsafe, said Bushra Khalidi, an official with Oxfam, an aid group working in Gaza.

Before the war, the coastal enclave's more than 2 million residents got their water from a patchwork of sources. Some was piped in by Mekorot, Israel's national water utility. Some came from desalination plants. Some was pulled from high-saline wells, and some imported in bottles.

Every source has been jeopardised.

Palestinians are relying more heavily on groundwater, which today makes up more than half of Gaza's supply. The well water has historically been brackish, but still serviceable for cleaning, bathing, or farming, according to Palestinian water officials and aid groups.

Now people have to drink it.

The effects of drinking unclean water don't always appear right away, said Mark Zeitoun, director general of the Geneva Water Hub, a policy institute.

“Untreated sewage mixes with drinking water, and you drink that or wash your food with it, then you're drinking microbes and can get dysentery,” Zeitoun said. “If you're forced to drink salty, brackish water, it just does your kidneys in, and then you're on dialysis for decades.”

Deliveries average less than three litres per person per day — a fraction of the 15-litre minimum humanitarian groups say is needed for drinking, cooking and basic hygiene. In February, acute watery diarrhea accounted for less than 20 per cent of reported illnesses in Gaza. By July, it had surged to 44 per cent, raising the risk of severe dehydration, according to UNICEF, the UN children's agency.

System breakdown

Early in the war, residents said deliveries from Israel's water company Mekorot were curtailed — a claim that Israel has denied. Airstrikes destroyed some of the transmission pipelines as well as one of Gaza's three desalination plants.

Bombardment and advancing troops damaged or cut off wells – to the point that today only 137 of Gaza's 392 wells are accessible, according to UNICEF. Water quality from some wells has deteriorated, fouled by sewage, the rubble of shattered buildings and the residue of spent munitions.

Fuel shortages have strained the system, slowing pumps at wells and the trucks that carry water. The remaining two desalination plants have operated far below capacity or ground to a halt at times, aid groups and officials say.

In recent weeks, Israel has taken some steps to reverse the damage. It delivers water via two of Mekorot's three pipelines into Gaza and reconnected one of the desalination plants to Israel's electricity grid, Deputy Foreign Minister Sharren Haskel told The Associated Press.

Still, the plants put out far less than before the war, Monther Shoblaq, head of Gaza's Coastal Municipalities Water Utility, told AP. That has forced him to make impossible choices.

The utility prioritises getting water to hospitals and to people. But that means sometimes withholding water needed for sewage treatment, which can trigger neighbourhood backups and heighten health risks.

Water hasn't sparked the same global outrage as limits on food entering Gaza. But Shoblaq warned of a direct line between the crisis and potential loss of life.

“It's obvious that you can survive for some days without food, but not without water,” he said.

Supply's future

Water access is steadying after Israel's steps. Aid workers have grown hopeful that the situation won't get worse and could improve.

Southern Gaza could get more relief from a United Arab Emirates-funded desalination plant just across the border in Egypt. COGAT, the Israeli military body in charge of humanitarian aid to Gaza, said it has allowed equipment into the enclave to build a pipeline from the plant and deliveries could start in a few weeks.

The plant wouldn't depend on Israel for power, but since Israel holds the crossings, it will control the entry of water into Gaza for the foreseeable future.

But aid groups warn that access to water and other aid could be disrupted again by Israel's plans to launch a new offensive on some of the last areas outside its military control. Those areas include Gaza City and Muwasi, where much of Gaza's population is now located.

In Muwasi's tent camps, people line up for the sporadic arrivals of water trucks.

Hosni Shaheen, whose family was also displaced from Khan Younis, already sees the water he drinks as a last resort.

“It causes stomach cramps for adults and children, without exception,” he said. “You don't feel safe when your children drink it.”