Waiwhetū means "star reflecting water" in Māori,[1] and is the name given to the original pā site in the area, the local marae, the suburb, and the stream.

The stream is around nine kilometres (5.6 mi) in length and passes through the eastern suburbs of Fairfield, Waterloo, and Waiwhetū, and the industrial areas of Seaview and Gracefield before entering the estuary of the Hutt River Te Awa Kairangi as it reaches Wellington Harbour.

[4][5] Prior to the 1855 Wairarapa earthquake, vessels large enough for coastal trade could navigate the lower reaches of the Waiwhetū stream, and there were several shipyards.

However, these plans were changed within a short time, after a large flood in the Hutt River persuaded the settlers that the town should be located at the opposite side of the harbour.

[10] From the earliest times of colonial settlement, the Waiwhetū Stream was the source of occasional floods that caused stock losses and damage to property.

[11] Heavy rain in July 1912 and August 1928 led to the Waiwhetū Stream overflowing its banks and flooding the nearby Hutt Park and surrounding area.

The flock mill operated for around 50 years, but was the subject of litigation in 1909–1910 that was heard in the Supreme Court over the effects of the flooding caused by the construction of the weir in the stream.

[21] In 1937, the committee managing Hutt Park considered a proposal to build a weir in the adjacent Waiwhetū Stream so that it could be used for bathing, even during low tide.

[22] In 1904, there was strong criticism of the Health Department for allowing the continuing discharge of sewage from thousands of patrons at the Hutt Park racecourse into the lower reaches of the Waiwhetū Stream.

[25] In April 1929, the Lower Hutt Borough Council made a provision of £6,250 for the construction of septic tanks near the outlet of the Waiwhetū Stream.

[36] During another heavy rainfall event in December 2021, there was another emergency discharge of sewage from a pumping station into the stream, leading to protests from local Māori.

[44] Mud in the stream bed down to a depth of 1.5 metres (4 ft 11 in) was heavily contaminated with lead, zinc, DDT and hydrocarbons including diesel, oil and petrol.

In 2003, it was estimated that there was 30,000 cubic metres (1,100,000 cu ft) of heavily contaminated sediment in a short section of the stream between Seaview Road and the rail bridge just north of Hutt Park Holiday Village.

[34][45] A major cleanup project commenced in 2009 to remove 12,000 cubic metres (420,000 cu ft) of contaminated mud from the lower reaches of the stream.

[48] One of the early tasks undertaken was the removal of the invasive aquatic plant Cape pond weed that had smothered the stream and impeded water flows.

[3]: 26  In 2023, the Friends of Waiwhetū Stream reported that annual sweeps of the river had shown that there are no longer any Cape pond weed plants present.

The temporary discharges cause pollution in the lower reaches of Waiwhetū Stream and in the estuary of the Hutt River, making it unsafe to collect shellfish, fish or swim in the area.