Water Contamination in Big Cities

The Journey Water Takes to Reach Your Tap in Dubai

Almost all water in the UAE starts as seawater in the Arabian Gulf. It passes through large

scale thermal  Reverse Osmosis desalination, bacteria control and then it is pumped into the DEWA distribution system. It then flows through the municipal pipes to your building, through a storage tank on the floor or roof of your building, and through your building's plumbing to the tap.

That is a long journey, and there are risks at each stop along the way, particularly in older structures where pipes and tanks aren't routinely examined.

Main Contamination Sources in Dubai's Urban Water Supply

Chlorine and chloramines from treatment

Chlorine is added to your water intentionally to prevent bacterial growth during distribution. It is not a contaminant in the sense of being harmful at the concentration detected in UAE tap water. But it does cause the characteristic pool-like taste and smell that makes many Dubai residents reluctant to drink tap water directly. It also reacts with organic material in pipes and creates disinfection by-products called trihalomethanes that, at high long-term exposure concentrations, have been linked to potential health effects. Activated carbon filters work very well for removing chlorine.

Sediment and rust from ageing pipes

Dubai has buildings ranging from brand new to over 40 years old. Some older buildings use galvanised steel pipes which can corrode over time, dissolving rust particles and, in some instances, small amounts of iron and lead into the water flowing through the pipes. This is more common in buildings built before the 1990s when pipe standards were different. These particles are drawn into a sediment filter and retained at the point of use.

Bacterial contamination from storage tanks

Most residential buildings in the UAE use rooftop water tanks as buffer storage. When these tanks are clean and properly sealed, they are safe. Bacterial growth may occur when water is not being maintained or if temperatures reach above 40 degrees F in summer and the water is left in the tank, or when the lid is not securely fastened. The biggest problem with warm stored water is Legionella. UV disinfection at the entrance to your apartment removes this risk altogether.

High TDS and mineral content

Dubai water typically carries TDS levels between 200 and 400 mg/L after treatment. This doesn't mean that the water is unsafe to drink, but elevated TDS has a big impact on the taste of the water, and some minerals found in high concentrations in the water, such as fluoride and nitrates, are preferable to keep in low concentration for families with babies and pregnant women. RO filtration reduces TDS to less than 50 mg/l.

Heavy metals from plumbing

Older plumbing systems may leach lead and copper from fittings and solder. There is no safe level of lead for children. This is a very real concern in a city where a lot of expat families reside in apartments which are of unknown pipe age. A quality RO membrane should be able to remove lead and copper to well below the recommended limit set by WHO.