The capacity of the Watercare infrastructure is limited because of the various pumping stations and the single sewerage line on the Peninsula. The plant required an increase in treatment capacity in 2019 due to rising sewage wastewater production from reticulated areas on the Hibiscus Coast, which includes Orewa and the Whangaparaoa Peninsula. Since that time the population has increased beyond the design parameters for that plant.
Housing intensification under the Governments National Policy Statement on Urban Development will place undue pressure on the capacity that will require an upgrade to Watercare's plant. However, there is no planned funding for that. The estimates are conservatively in excess of $1 billion but there is no business case underway so capacity is very unlikely to be increased in the near future.