盐水就是在一杯水中，加入了食盐，就称作盐水。早在古代前，古人就已经发现了这种水的存在。

盐水功能非常的多样化，在此一一介绍。

当家中有灰尘或污垢时，在肮脏处泼上一些盐水，即可达到杀菌的效果，原理为利用盐水的渗透压，令细菌失去水分。另外如果家中大扫除时在角落洒一些盐水，也可以避免蟑螂及其他蚊虫的侵入。

有时我们会看到一些人把水果泡在盐水里一阵子再拿出来食用，也是个不错的方法。其实这么作可以保持水果的新鲜，也比较不容易腐坏。另外我们还可以在蛋糕上面洒少量盐水，可以把甜味引诱出来，增加它的风味。

Saline water (more commonly known as salt water) is water that contains a significant concentration of dissolved salts (mainly NaCl). The salt concentration is usually expressed in parts per thousand (permille, ‰) or parts per million (ppm). The United States Geological Survey classifies saline water in three salinity categories. Salt concentration in slightly saline water is around 1,000 to 3,000 ppm (0.1–0.3%), in moderately saline water 3,000 to 10,000 ppm (0.3–1%) and in highly saline water 10,000 to 35,000 ppm (1–3.5%). Seawater has a salinity of roughly 35,000 ppm, equivalent to 35 grams of salt per one liter (or kilogram) of water. The saturation level is dependent on the temperature of the water. At 20 °C one milliliter of water can dissolve about 0.357 grams of salt; a concentration of 26.3%. At boiling (100 °C) the amount that can be dissolved in one milliliter of water increases to about 0.391 grams or 28.1% saline solution.