Journal//5 min read
Is Dubai tap water hard or soft? What DEWA's own figures say
By its utility's own published figures, Dubai's tap water is soft. DEWA's Sustainability Report 2025 gives a total hardness specification of 40–120 mg/L as CaCO₃ and a typical value of 60.7 mg/L — about 3.4 °dH, or 0.61 mmol/L. That is a figure at production, not a measurement at your tap, but nothing published supports the 120–400 mg/L that many softener sellers quote.
Ask whether Dubai water is hard or soft and you get two answers that cannot both be right. Many sellers of softeners and filters call it hard and quote 120 to 400 mg/L. The utility that produces the water publishes a hardness specification whose ceiling is 120 mg/L, and a typical value of about half that. This piece sets out what DEWA actually publishes, what it does not, and what the number means for an espresso machine.
Where Dubai's water comes from
Nearly all of Dubai's drinking water is desalinated seawater. Desalination removes almost everything dissolved in the sea, minerals included, and water that pure is not put into the network as it is: it is remineralised first, with calcium and alkalinity added back in controlled amounts. So the hardness in a Dubai tap is not geological, as it is across most of Europe. It is a dose, set at the plant.
What DEWA publishes
DEWA's Sustainability Report 2025 includes a table of potable water quality at its Jebel Ali production complex. It reads:
- Total hardness — specification 40–120 mg/L as CaCO₃; typical value 60.7 mg/L, which is about 3.4 °dH or 0.61 mmol/L.
- Calcium 15.9 mg/L and magnesium 5.1 mg/L — which, by the standard conversion, add up to the same 60.7.
- M-alkalinity — about 49–51 mg/L.
- Total dissolved solids — about 216–254 mg/L.
The earlier reports gave typical hardness of 61.9 mg/L (2023) and 61.3 mg/L (2024): a steady number, not a lucky one. On the German scale, where water below 8.4 °dH counts as soft, 3.4 °dH is comfortably soft. On the US Geological Survey scale, which draws the soft line at 60 mg/L, it sits right on the boundary with moderately hard. On no common scale is it hard.
For coffee, the SCA Water Chart puts its target zone at roughly 50–110 ppm CaCO₃ of hardness. A typical 60.7 sits inside it, towards the soft end. The listed alkalinity, if read as CaCO₃ — the usual convention — would also fall inside the chart's 40–65 zone. On paper, Dubai's water is not an extreme in either direction.
Where the 120–400 mg/L figures come from
Many companies selling softeners and filters in Dubai describe the water as hard and quote 120 to 400 mg/L. We have not found a public dataset behind those numbers. They sit at or above the ceiling of DEWA's own specification. They may describe individual tests in individual buildings; they do not describe the water DEWA says it supplies.
There is a real caveat, and it is the honest version of their argument. Between the plant and your tap, Dubai water usually passes through building storage tanks and private pipework, and those can change water quality. What no public data does is quantify a change in hardness along that route. If you want to know what comes out of your tap, the only reliable answer is to measure it.
What it means for an espresso machine
Limescale is calcium carbonate precipitating when water is heated, and it is driven by carbonate hardness — calcium and bicarbonate together. At a typical 60.7 mg/L, Dubai's network water carries far less of it than the hard waters common across much of Europe, so the scale risk is correspondingly low. Low is not zero, and your tap may differ from the plant. Follow your machine maker's descaling guidance, set the machine's hardness setting from a measured value rather than a guess, and do not buy a softener on the strength of a number nobody has measured at your tap.
Where this leaves our own recommendation: by our thresholds, DEWA's published figure falls in the band we built Leucosia for. That is our recommendation, not a finding — no study validates a blend-to-water pairing, and our page on what we do not claim says so in detail.
Abu Dhabi, and the emirates with no published figure
Abu Dhabi's water is also predominantly desalinated. The most specific figure we found is in the Statistics Centre – Abu Dhabi's Water Statistics, 2018 edition, Table 1.3: an emirate-wide network average total hardness of 50.08 mg/L as CaCO₃, across 4,186 samples. It is an average over the whole emirate and it is several years old, so treat it as indicative. The Department of Energy's Water Quality Regulations 2025 set a maximum of 300 mg/L — a legal limit, not a measured value.
For Sharjah (SEWA) and the emirates served by Etihad Water and Electricity, we could not find any published hardness values. We would rather say so than fill the gap with an estimate.
How to test your own water
- A TDS meter does not measure hardness. It estimates all dissolved solids from conductivity, sodium and chloride included. DEWA's own table shows the gap: about 216–254 mg/L of TDS against 60.7 mg/L of hardness.
- For hardness, use total-hardness test strips or a GH drop test. For alkalinity, use a KH drop test. Aquarium GH/KH kits are inexpensive and read in °dH; multiply by 17.85 to get mg/L as CaCO₃.
- Test the tap you actually brew from, more than once. If your building or kitchen has a filter or a softener, test before and after it.
Questions this raises
- Is Dubai water hard or soft?
- By DEWA's published figures, soft. The utility specifies total hardness of 40–120 mg/L as CaCO₃, with a typical value of 60.7 mg/L at production. That is soft on the German scale and on the boundary between soft and moderately hard on the US Geological Survey scale. It is not a tap measurement, so your building may differ.
- What is Dubai's water hardness in °dH or mmol/L?
- DEWA's typical 60.7 mg/L as CaCO₃ is about 3.4 °dH, 6.1 °f, or 0.61 mmol/L. The specification range of 40–120 mg/L corresponds to about 2.2–6.7 °dH, or 0.4–1.2 mmol/L.
- Is TDS the same as water hardness?
- No. TDS counts every dissolved solid, including sodium and chloride; hardness counts only calcium and magnesium. A TDS meter cannot tell them apart. In DEWA's figures, TDS is roughly three and a half to four times the hardness.
- Should I soften Dubai tap water for my espresso machine?
- Not on the strength of DEWA's figures alone. At around 60 mg/L the scale risk is low, though not zero, so measure your own tap first. If you do treat the water, note that a sodium ion-exchange softener removes hardness but leaves alkalinity unchanged — the combination the SCA Water Chart labels weak, chalky and flat.
- Is Abu Dhabi water hard or soft?
- Soft too, by its published figures. The Statistics Centre – Abu Dhabi's Water Statistics (2018 edition) reports an emirate-wide network average of 50.08 mg/L as CaCO₃ across 4,186 samples. The 300 mg/L in the 2025 Water Quality Regulations is a legal maximum, not a measured value.