Yes, it is considered safe to consume tap water in Istanbul. The ISKI (Water authority of Istanbul) treats the tap water before it is delivered to consumers. Nonetheless, we’ve read that some structures in the larger cities have outdated pipes and reservoirs, which might cause water pollution. This is beyond the control of the ISKI.
There is a tiny amount of free chloride in the water, which is difficult to detect. However, because of the chloride and long retention time in the pipes, the water in Istanbul may not taste or smell as nice as soft natural groundwater that can be found in other parts of Turkey. Locals dislike the taste of tap water and would rather not drink it.
Cleaning and cooking with tap water are both fine, but drinking it isn’t. In certain smaller towns, tap water may be clean enough to drink; nevertheless, in major cities such as Istanbul, Ankara, Izmir , etc., bottled water should be utilized instead. When it comes to brushing their teeth, all locals use tap water.