A suggestion new builds in Waikato should foot the bill for new water infrastructure, to protect existing households from rising costs.

The new water services company IAWAI is proposing water supply and wastewater growth charges of $500 per year for 25 years on all new residential builds.

Over ten years, the charges would generate $46.3 million dollars.

Chief executive Peter Winder says it's important to ensure growth is funded - but existing customers aren't hit with extra charges. 

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