Under the draft Auckland Unitary Plan, all applicants for resource consent for new or existing developments must apply to iwi for them to assess whether it would have an adverse effect on mana whenua.
Taking or using groundwater is on the list of activities that could have a cultural impact, so iwi may insist on a cultural impact assessment - at the applicant's cost.
Applicants may also have to foot the bill for the "costs of engagement" in the process.
The Tassells will meet Labour MP Shane Jones, who has been vocal in his disagreement with iwi approval rules.
He warned the new Auckland Council lacked safeguards.
"Maori heritage, while it's important, it must never be used as a basis for divisiveness - and I fear that's a consequence in this case," he said.
Iwi should not be allowed to intervene to "test whether there's a taniwha down a 10-year-old bore".
An Auckland Council spokeswoman admitted the new rules placed "additional burdens" on applicants, and said the council was working with iwi to streamline the process.
But Brent slammed the application process as "unworkable" for ordinary Aucklanders who would foot the bill for cultural assessments. If denied, they and the other families on the lane - will need to install rain water tanks costing thousands of dollars.
Jennifer added: "It's an extra burden on your average Joe on the street."