Jewish laws with regard to Mikveh are extensive. The most notable aspect of these laws is that a Mikveh must be filled with "living water," namely, water that has come directly from the earth in the form of caught rainwater or spring water (water flowing in a river or stream is also acceptable in some cases). Once water has been carried in a vessel or run through a pipe, it is no longer considered "living." Additionally, immersion must be complete (including the head and hair), and there can be nothing between the water and the person immersing—not only clothing, but also makeup and jewelry are removed. The common practice is to wash thoroughly before immersion (to remove any dirt or dead skin on the body), and to enter the Mikveh while still wet (to avoid any air bubbles that might be trapped on the skin or in the hair).