Can I use wet wipes instead of water for istinja (cleaning after using the toilet)?

Istinja (cleaning after using the toilet) can be done with water, with dry cleaning material (tissue, or historically stones — called istijmar), or a combination, and many contemporary scholars extend this to plain, unscented, alcohol-free wet wipes provided they actually leave the area clean with no visible or felt trace of impurity remaining. That said, this is genuinely one of the few areas where scholars differ in practice: some fatwa bodies hold that wipes alone are not sufficient, particularly after urination, because urine is a liquid impurity that classical fiqh generally expects to be removed with water rather than dry material alone.

The safer and more widely recommended approach, especially after urination, is to use water if at all possible, since it's the method with the least scholarly disagreement and the most thorough in actually removing impurity rather than just spreading or masking it. If water genuinely isn't accessible (public restrooms without a bidet/jet spray, travel situations, etc.), using enough plain wet wipes to thoroughly clean the area — continuing until a wipe comes away clean — is accepted as valid by a good number of contemporary scholars, though using water afterward when you do get the chance is still preferable.

Source: general fiqh on istinja/istijmar; contemporary fatwa discussion on plain wet wipes as a substitute for water, e.g. SeekersGuidance and comparable Hanafi fatwa services.