Purification is valid with any water that remains in its natural created state — rain, wells, rivers, springs, melted snow or hail, and sea water — and water is presumed pure and purifying unless its color, taste, or smell is genuinely changed by an impurity. When a man asked the Prophet about performing wudu with sea water, fearing to run out of fresh water at sea, he answered: "Its water is purifying and its dead (creatures) are lawful." So sea water is not merely tolerated but is explicitly declared a means of purification, and Allah described the rain He sends down as pure water to purify us.
Evidence — the daleel
On deen2u
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.