This distance is regarded and is customarily described as being close, so what you must do is go to the water and do wudu’ with that water, and do ghusl if you have to do ghusl, and it is not permissible for you to do tayammum in this case, because the distance of ten minutes or a quarter of an hour is regarded as close, and customarily is not regarded as being far away. There is no excuse not to do wudu’; rather whether you are at work or on a journey, you must go to this water and do wudu’ as prescribed in Islamic teachings, and if you are junub you must do ghusl, and then pray. This distance is not an excuse to do tayammum, because it is customarily regarded as being close.
End quote from Fatawa Nur `ala ad-Darb, 2/653.