Gaza City - Water may be a highly valued commodity the world over - but in al-Shati refugee camp north of Gaza City, it is like gold.

Along this small stretch of the Mediterranean coast, all it takes to work that out is turning on a tap: When it is there at all, the water is salty, or sometimes cloudy.

Nahed Radwan, who lives with her eight children and extended family in a pastel-painted house by the sea road, said her family normally gets water once a week for two days.

"The water we have, when it's on, it's not clean; it's undrinkable. It hurts the eyes because of the high salinity," Radwan, 34, told Al Jazeera.

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Only an estimated 3 percent of Gaza's water is suitable for drinking. The Palestinian Water Authority and the United Nations have warned that its underground water aquifer - upon which the territory is almost entirely reliant, apart from a small amount of water imported from Israel - may be completely contaminated by the end of the year. Gaza's water contains a large concentration of chloride, while infiltration of untreated sewage has raised the levels of nitrates to two to eight times higher than the World Health Organization recommends.

Gaza is also gripped by an electricity crisis that sometimes leaves households with just a few hours of power a day.

"People are using generators for water, but we can't afford it," Radwan said. "Especially my girls - they don't like to take showers with salty water, their hair starts to fall out. I cook and do everything with drinking water."

The water we have, when it's on, it's not clean; it's undrinkable. It hurts the eyes because of the high salinity. Nahed Radwan, Gaza resident

Many Palestinians in Gaza buy water from small-scale desalination plants, which filter the contaminated aquifer water. Private vendors distribute the water to residents using trucks. But b y the time the water reaches household tanks, it is expensive - up to five times the price of water from the municipal network - and often not safe to drink. Fewer than half of Gaza's desalination facilities are licensed, according to Oxfam.

International NGOs working in the water sector in Gaza have found that 68 percent of the water that reaches households from these plants becomes biologically contaminated during storage or transportation, yet 85 percent of Palestinians in Gaza depend on this water for drinking and cooking. EWASH, a coalition of Palestinian and international organisations working in the water and sanitation sector, says that low-income households in Gaza spend at least six times more of their income on water than their counterparts in the United Kingdom.

The recent Turkey-Israel deal is expected to provide some relief, allowing Turkey to work on a number of infrastructure projects in Gaza, including a power station and a desalination plant. Ribhi al-Sheikh, deputy head of the Palestinian Water Authority, told Al Jazeera he did not yet have details of the project.

At least 70 percent of the materials needed to build and maintain Gaza's water and sanitation network - including pumps and chemicals for water purification - are subject to severe entry restrictions amid Israel's siege on Gaza, according to EWASH. The lack of proper infrastructure has contributed to pollution: Every 38 minutes, the coalition found, the equivalent of one Olympic swimming pool of raw or partially treated sewage is discharged into the sea in Gaza.

Over-extraction from Gaza's aquifer at twice the sustainable rate has led to the infiltration of seawater, contributing to the degradation of water quality. Unregulated wells - which Palestinians in Gaza have been digging, both for agricultural and household use - have compounded the problem of over-extraction.

"The scarcity of water [in Gaza] is the problem or the crisis of the time," Najma Fares, a researcher at al-Azhar University's Water and Environment Institute, told Al Jazeera. "Because of the abuse or extraction of this water, in the next years Gaza will face a big problem that could endanger the lives of Gazans. It will be an environmental catastrophe."

Fares, who worked on a pilot project to treat waste water from a factory in central Gaza for immediate reuse in agriculture, said the implementation of such a scheme would need considerable funding.

Some funding for this sector has come from international donors, including the European Union, which invested $11m in a new seawater desalination plant in Gaza that was inaugurated in June . Over the next three years, a second phase of the project aims to double its capacity, allowing the plant to serve an estimated 150,000 people in southern Gaza.

Critics, however, say such efforts do not go far enough.

"The problem is not in securing the funds or the grant for implementing these desalination projects. The problem comes afterwards. Who will operate it; who will pay the bill for this?" said Mahmoud Shatat, the programme manager for Oxfam's Water, Sanitation and Hygiene Promotion programme. "How can we afford the electricity and the fuel? Solar energy only covers a small amount of what's needed to run a desalination plant."

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Small-scale seawater desalination plants have high operating costs, and are meant to be a mid-term solution. The Palestinian Water Authority said a large-scale plant able to serve all of Gaza should be operational by 2020 - but while Gulf countries and France have pledged funding towards its estimated cost of $330m, more is required.

Marwan Albardawil, the authority's head of water and waste water projects, said a variety of options to tackle Gaza's water crisis have been studied over the years. "Among these, there was importing water from Egypt, Turkey and Israel; delivering water from the West Bank to the Gaza Strip; and seawater desalination. The proper option was desalination," Albardawil told Al Jazeera.

A study conducted in 2011 as part of the Gaza Emergency Technical Assistance Programme recommended the transfer of high volumes of water from Israel, in order to give Gaza an equitable share of regional water resources. However, water-sharing arrangements are supposed to be part of the long-awaited final status peace negotiations.

Clemens Messerschmid, a geologist who has worked in the Palestinian water sector for 20 years, said the source of Gaza's water problem is its large population, which has skyrocketed to more than 1.8 million. A simple solution would be for Gaza to buy water from Israel, which has a surplus in the south, he said.