Water pump apparatus

A water pump apparatus, comprising:

• a body adapted to fix to a mounting surface of an engine and having a bore;
• a rotational shaft rotatably supported on the body via a bearing;
• an impeller fixed to the shaft and located in a pump chamber for forcibly supplying water from a water inlet to a water outlet, a seal member for sealing between the pump chamber and the bore of the body;
• and
• a collection chamber portion provided on at least one of the body or the engine so as to communicate with the bore between the bearing and the seal member via a drain passage and for collecting water leaked via the seal member,
• wherein the collection chamber portion is opened toward the mounting surface of the engine, and an opening of the collection chamber portion is fluid-tightly closed by fixing the body to the engine,
• the collection chamber portion is communicated to the atmosphere via a drain port which is formed on the body or the engine, and
• one of a dye-proofing process layer, a water repellent process layer or a decomposition process layer for decomposing a solid is formed on an outer wall surface of the body or the engine which is adjacent to the drain port.