Salt Questions · Science, chemistry & environment
Why do some lakes have higher salt concentrations than the ocean?
Short answer
Lakes with no outlet to the sea, called endorheic or terminal lakes, lose water only by evaporation. Rivers keep bringing in dissolved minerals, but the water leaves as pure vapour, so salt builds up. In hot, dry climates this concentrates salt far beyond seawater: the Dead Sea is about 34% salt, nearly ten times saltier than the ocean.
Salinity, per cent
No way out
Most lakes drain through a river to the sea, which flushes salts away. An endorheic lake sits in a closed basin: water comes in, but the only exit is evaporation. Every year's dissolved minerals stay behind.
Famous salt lakes
- Dead Sea (Jordan, Israel, West Bank): about 34% salt.
- Great Salt Lake (Utah): about 5–27%, varying with water level and between its arms.
- Don Juan Pond (Antarctica): over 40%, mostly calcium chloride, one of the saltiest bodies of water on Earth.
Changing salinity
Salinity rises when lake levels drop. Water diversions have lowered several salt lakes, concentrating them further and exposing dusty lakebeds.
Related on The Salt Almanac
More science, chemistry & environment questions
- How does road salt cause cars to rust so quickly?
- What is the boiling point of a saturated salt water solution?
- How do desalination plants turn ocean water into drinking water?
- Why does salt dissolve faster in hot water than cold water?
- What is rock salt made of?
- How does salt water affect the density of water?
Cite this page
For school projects and reports. Teachers often prefer the original sources too: see the list below.
The Salt Almanac. (2026, November 8). Why do some lakes have higher salt concentrations than the ocean. https://saltalmanac.com/answers/why-do-some-lakes-have-higher-salt-concentrations-than-the-ocean
“Why do some lakes have higher salt concentrations than the ocean.” The Salt Almanac, 8 Nov. 2026, saltalmanac.com/answers/why-do-some-lakes-have-higher-salt-concentrations-than-the-ocean. Accessed [today's date].
“Why do some lakes have higher salt concentrations than the ocean.” The Salt Almanac. Last modified November 8, 2026. https://saltalmanac.com/answers/why-do-some-lakes-have-higher-salt-concentrations-than-the-ocean.
Original sources
- Wikipedia. Endorheic basin. https://en.wikipedia.org/wiki/Endorheic_basin
- Wikipedia. Dead Sea. https://en.wikipedia.org/wiki/Dead_Sea
- Wikipedia. Great Salt Lake. https://en.wikipedia.org/wiki/Great_Salt_Lake