Water purifier

A water purifier for killing bacteria in water located in a confined area, comprising:

• a housing having a water inlet that permits the water to enter the water purifier and a water outlet that permits water to exit from the water purifier;
• a cover that is removably attachable to said housing;
• a purification unit removably positioned between said cover and said housing;
• a first fluid path located between said water inlet and said water outlet so that water flowing along said first fluid path flows from the water inlet to the water outlet without flowing through said purification unit, said first fluid path including a constricted region having a cross sectional area that is smaller than a cross sectional area of said water inlet;
• a second fluid path located between said water inlet and said water outlet, and including said purification unit so that water flowing along said second fluid path flows through said purification unit;
• an indicator for indicating the level at which water is flowing through the purification unit;
• a shutoff valve that is configured to shut off flow through the second fluid path without reducing flow through the first fluid path;
• and
• a self-adjusting flow regulator positioned within said constricted region, said self-adjusting flow regulator automatically modifying the cross sectional area of said constricted region to maintain a rate of flow along said second fluid path within a predetermined range as water flows from said water inlet to said water outlet at a variable rate,
• wherein said self-adjusting flow regulator comprises a material that flexes under pressure.