A house pump is a booster pump that increases the potable water pressure. You may use the pump to boost the municipal water pressure if the pressure was not adequate for the shower, etc.
A house pump could be an ejector pump, but a house pump is not always an ejector pump.
bimr has explained the normal meaning of house pump, but bear in mind that in most countries/water supply authorities will not allow a booster pump to be connected direct to their main supply system, you require a holding tank which is feed from the main and to which the house pump would be connected. In the case of your own system where you supply the water from a dam, well etc., you can arrange it in anyway to suit yourself.
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
