traderstu:[snip] The couple that I have googled acknowledge that taking water for domestic purposes is expressly allowed under the RMA (law), but they do impose conditions (rules) around compliance (eg over-allocation, protection of wetlands, etc)
This is the key here. Whilst resource consent may not be required, that is only one of several rules that could be applicable here. Without further information it's not clear whether what the OP is proposing is allowed. The appropiate local body or council for the OP's area needs to be determined and contacted.