If a person feels that droplets of urine have reached his body, but does not know the quantity, then forgets to check or purify, is it permissible for him to assume that the impurity is slight and excusable, and to consider his prayers valid and his clothes and sitting places pure?

Most scholars hold that urine, even if it is a small amount, is not excused and must be washed off.

However, some scholars, such as the Hanafis, permit an exemption for urine spray. Their school of thought allows for the pardon of severe impurities (like urine) if they do not reach the amount of a dirham (in weight for solids and in surface area for liquids).

According to the Hanafi view, if a person doubts whether the impurity exceeded this amount or not, the default assumption is that it did not.

Nevertheless, the most cautious and absolving opinion is that of the majority, which states that there is no pardon for a small amount of urine, and whatever it touches must be purified absolutely.