Between 16,000 and 18,000 housing units have been severely damaged or totally destroyed, the United Nations Development Program estimates, leaving tens of thousands not just homeless, but with nothing left but the clothes they were able to evacuate with.

On a wider scale, almost every piece of critical infrastructure, from electricity to water to sewage, has been seriously compromised by either direct hits from Israeli air strikes and shelling or collateral damage.

As many as 520,000 Palestinians have been displaced from their homes in Israel’s nearly four-week long military campaign and with this temporary ceasefire, many are only now able to fully grasp the extent of the devastation in their neighbourhoods.

Shocked families wordlessly picked through the rubble of their houses in northern towns of Shujaiya and Beit Hanoun, where the smell of death still hangs in the air.

Rescue workers are still pulling bodies from under rubble – after successive humanitarian ceasefires broke down over the last week, there has been little access until now to some of the worst-affected neighbourhoods.

There was no celebration of the ceasefire – the first to have lasted more than a few hours since this conflict began on July 8 – or of the fact that Israeli ground troops had withdrawn from Gaza after announcing they had destroyed 32 Hamas tunnels and significant weapons caches.

Instead, Gaza was blanketed in grief and loss.

Gaza officials say that 1834 Palestinians have died in the conflict, most of them civilians, including more than 400 children. Israel says 64 of its soldiers and three civilians have been killed since fighting began on July 8.

Some people were able to retrieve a handful of clothes or non-perishable items such as nappies or tinned goods, while others in rural areas like the southern town of Khuza'a emerged from their devastated homes with nothing more than a bag of lemons or a container of olives they had been pickling.

Israel says it has destroyed much of Hamas’ weapons stores and more than 30 tunnels during its 28-day operations in Gaza, but it is clear, says the UNDP’s special representative of the administrator in the occupied Palestinian Territory Frode Mauring, that they have destroyed so much more.

“The current situation is devastating,” he said. “There will be a lot of people who cannot return to their homes.”

There can be no real recovery, he warned, until both Israel and Egypt lift their siege on Gaza, implemented in 2007 when Hamas took control of Gaza after winning elections in 2006.

Although Israel withdrew from Gaza in 2005, it maintains extremely strict controls over both people and goods entering and leaving the strip, keeping Gaza in almost complete lockdown from the land, air and sea.

Egypt rarely opens its Rafah crossing with Gaza, meaning most Gazans are trapped between the two countries with ever-diminishing prospects for employment, business, health care or travel.

And two consecutive wars with Israel – in 2008/9 and 2012 – had already left critical infrastructure badly in need of repair and struggling to cope with Gaza’s growing 1.8 million population.

“We cannot have a situation where we continue to take 20 months to get approvals from [Israel] to do construction,” says Mr Mauring, who notes there has not been a single new construction project approved in Gaza since May 2013.

“If this situation continues we cannot talk about the recovery of Gaza because the recovery of Gaza is going to require building materials” that are either banned from entering Gaza or only allowed in on a severely limited basis.

Already vulnerable before this latest crisis, Gaza’s main water supply and wastewater infrastructure has been hit hard by Israeli air strikes and shelling over the past 29 days.

As a result the water supply and sewage services to 1.2 million people, or two-thirds of Gaza’s population, have been cut or severely disrupted.

Three direct hits on Gaza City’s main sewage plant means at least 30 million litres of untreated sewage each day is now pouring into the Mediterranean Sea off Gaza’s coast, says Monzir Shublaq, the director-general of the Coastal Municipal Water Utilities.

Vital repair work had to be suspended when four water technicians were killed in Israeli air strikes as they tried to fix the damage, he says.

“If we are able to secure funding and the blockade is lifted we should be able to do the repairs in a month, but if the blockade is not lifted it will take much longer because we need cement to do the repairs,” he said.

It is a similar story with Gaza’s main power station, which was taken out of action in an air strike on July 29.

Its head of distribution, Majdi Yaghi, says it will take up to a year to repair without Israel’s co-operation on the parts and equipment needed to get it working anywhere near full capacity.

“Right now people in Gaza City – who are in the best position – are getting around two hours of electricity a day,” Mr Yaghi says.

“Those in Khuza'a have no power at all – it has been completely destroyed – while in the north in Beit Lahiya, Beit Hanoun and Shujaiya are also badly affected.”

Added to that, the company has lost $US35 million in cables, transformers and stores destroyed in the air strikes.

Repeated questions to the Israel Defence Forces regarding whether critical infrastructure had been deliberately hit in its operations in Gaza have yet to be fully answered.

“The power plant strike is being investigated,” says Lieutenant-Colonel Peter Lerner, a spokesman for the IDF. “We have not been able to determine who carried out the strike.”

As for the sewage plant? “We have evidence that a rocket was fired from that plant,” Colonel Lerner says.

Mr Mauring says everything in Gaza is affected by the destruction of the electricity infrastructure, resulting in significant humanitarian consequences.

“The siege must be lifted in a way that allows Israel to feel safe about opening its borders and satisfies the needs in Gaza,” he says, warning: “The status quo is not a viable option.”