It has been claimed that the deteriorated state of the three waters infrastructure is the result of 50 years of under-investment, and that large increases in rates for water services will be necessary. The cause of these leaks is due to the nature of the city reticulation systems. For example, MDPE pipe was used in Porirua and there were many failures (leaks) on relatively new pipes. The cause was poor backfilling of the trench when under construction. Plastic pipes require backfill material to be soft, eg: sand and any stones or rocks inadvertently finding their way into the trench can cause failure and leaks. Another cause of failure in Porirua City’s reticulation was and is the ongoing failure of Asbestos Cement (hereafter AC) pipes, AC pipes were destined and created by an Austrian, Dr Mazzi, but he did not forsee that over time, the pipes would absorb water, swell and ultimately fail. Being somewhat brittle, these pipes were also not very resistant to poor backfill, rocks and stones.Finally, in contradistinction to steel welded Bulk Water Pipes, which form a leak free system (when welds are properly x-rayed and pipes pressure tested, city reticulation systems use mechanical joints, either push in joints, Gibault Joints or their modern successors, sleeve joints (made by Viking Johnson in the UK and abroad and Dresser in America, primarily for oil pipelines) , all of which rely on a rubber seal. Historically, the rubber used was natural rubber which deteriorates even when not exposed to sunlight. EPDM, a synthetic rubber, is now used for these modern sleeve joints and also in gate valves as a lining to separate the valve body from the potable water, thus avoiding contamination. Other possibilities for leak causation is the use of inferior materials. For example, an air valve near a road may have a small copper pipe between the main pipe and the air valve. Constant vibration from traffic may cause the slender pipe to fail as it is connected to a relatively heavy valve, if not supported properly. Here, a stainless steel, hard material is a better design. One more and there are many more reasons for leaks is the failure to install thrust blocks on valves and bends, not a problem on an integral steel system but catastrophic for a jointed connection using rubber as on closing the valve or pressurising the bend, the pipe is subject to a force of value, cross sectional area multiplied by pressure. Such failures can rip a jointed system to pieces.
It has been claimed that the deteriorated state of the three waters infrastructure is the result of 50 years of under-investment, and that large increases in rates for water services will be necessary. The cause of these leaks is due to the nature of the city reticulation systems. For example, MDPE pipe was used in Porirua and there were many failures (leaks) on relatively new pipes. The cause was poor backfilling of the trench when under construction. Plastic pipes require backfill material to be soft, eg: sand and any stones or rocks inadvertently finding their way into the trench can cause failure and leaks. Another cause of failure in Porirua City’s reticulation was and is the ongoing failure of Asbestos Cement (hereafter AC) pipes, AC pipes were destined and created by an Austrian, Dr Mazzi, but he did not forsee that over time, the pipes would absorb water, swell and ultimately fail. Being somewhat brittle, these pipes were also not very resistant to poor backfill, rocks and stones.Finally, in contradistinction to steel welded Bulk Water Pipes, which form a leak free system (when welds are properly x-rayed and pipes pressure tested, city reticulation systems use mechanical joints, either push in joints, Gibault Joints or their modern successors, sleeve joints (made by Viking Johnson in the UK and abroad and Dresser in America, primarily for oil pipelines) , all of which rely on a rubber seal. Historically, the rubber used was natural rubber which deteriorates even when not exposed to sunlight. EPDM, a synthetic rubber, is now used for these modern sleeve joints and also in gate valves as a lining to separate the valve body from the potable water, thus avoiding contamination. Other possibilities for leak causation is the use of inferior materials. For example, an air valve near a road may have a small copper pipe between the main pipe and the air valve. Constant vibration from traffic may cause the slender pipe to fail as it is connected to a relatively heavy valve, if not supported properly. Here, a stainless steel, hard material is a better design. One more and there are many more reasons for leaks is the failure to install thrust blocks on valves and bends, not a problem on an integral steel system but catastrophic for a jointed connection using rubber as on closing the valve or pressurising the bend, the pipe is subject to a force of value, cross sectional area multiplied by pressure. Such failures can rip a jointed system to pieces.
Finally, for your perusal; in Wellington, earthquakes, even small tremors, cause failures and leaks, especially in the historic cast iron pipes. These can easily crack and experience catastrophic brittle failure (impossible in steel pipelines unless the pipe is subjected to abnormally low temperatures – not really possible in New Zealand. The pipelines are in significantly worse condition than those in other large networks nationwide, and there has been a recent history of serious failures. The water supply to the region is also at significant risk because of the high rate of leakage, and it is also vulnerable during a severe earthquake, although some projects are underway to improve resilience.
Finally, for your perusal; in Wellington, earthquakes, even small tremors, cause failures and leaks, especially in the historic cast iron pipes. These can easily crack and experience catastrophic brittle failure (impossible in steel pipelines unless the pipe is subjected to abnormally low temperatures – not really possible in New Zealand.
An earthquake mitigation and preparedness report was procured from Opus, now WSP consultants (to be confirmed) and the report led to the acquisition of spare large diameter pipes, which were deposited in two pipe dumps, one at Gear Island and the other near Grenada North on the Te Marua to Karori pipeline. The spare pipes were sealed off and buried to prevent deterioration of the tape coating. The idea was, that in the event of an earthquake, a large digger (excavator) would first uncover the pipes and then be used to transport the pipes to the location of any bursts, as roads may be unable to be used after an earthquake event. The maintenance depot at Mabey Road, Lower Hutt, contained the spare couplings required and had preparedness measures implemented, such as beds, emergency food, and most importantly, a 10,000 litre pressurised water tank to ensure constant water turnover prior to chlorination, by re-purposing a redundant surge vessel once used at the Ngaio pump station. Even the seat of government, the Beehive, only had 15,000 litres of emergency water.}}
An earthquake mitigation and preparedness report was procured from Opus, now WSP consultants (to be confirmed) and the report led to the acquisition of spare large diameter pipes, which were deposited in two pipe dumps, one at Gear Island and the other near Grenada North on the Te Marua to Karori pipeline. The spare pipes were sealed off and buried to prevent deterioration of the tape coating. The idea was, that in the event of an earthquake, a large digger (excavator) would first uncover the pipes and then be used to transport the pipes to the location of any bursts, as roads may be unable to be used after an earthquake event. The maintenance depot at Mabey Road, Lower Hutt, contained the spare couplings required and had preparedness measures implemented, such as beds, emergency food, and most importantly, a 10,000 litre pressurised water tank to ensure constant water turnover prior to chlorination, by re-purposing a redundant surge vessel once used at the Ngaio pump station. Even the seat of government, the Beehive, only had 15,000 litres of emergency water.
In the mid 1990s, city reservoirs supplied by the Bulk Water Pipelines were retrofitted with dedicated non-return valves (rather than re-plumbing the inlet control valves to provide non-return function) to prevent water loss should the inlet pipe fracture and leak, thus draining precious, needed water. Regarding the Silversteam bridge, the original proposed scheme was to make a diversion across the Manor Park Golf Club, home to Michael Campbell incidentally) and use a new method of allowing the pipe to deflect in a trench of soft backfill. Normally, thin wall pipes require a solid backfill to reduce the working stress on the pipe; this increase in pipe wall thickness was part of the design (tbc) Now, this scheme and a new combined road/pipe bridge as a replacement of the old bridge, which had pipes joined mechanically is the plan.
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Still need to add more content about stormwater generally, and about wastewater in regions other than the Wellington urban area. In particular, need to add content about the significant failures in the wastewater system in Wellington City in 2019 and 2020 (collapse of pipeline beneath Dixon St leading to harbour spill and emergency construction of above-ground pipeline in Willis St, plus separate failure of sludge pipeline beneath Mt Albert and trucking of sludge during the investigation and repair). Marshelec (talk) 23:25, 13 April 2020 (UTC)
- Good work! Schwede66 19:07, 14 April 2020 (UTC)
I left the following feedback for the creator/future reviewers while reviewing this article: Nice work!.
North8000 (talk) 23:24, 15 May 2020 (UTC)
I have moved the full content about drinking water to a new article Water supply in the Wellington region, because the this article was getting a bit long, and I intend to expand content about stormwater and wastewater over the next week or so. I may still prune back the content in this article about drinking water a bit further.Marshelec (talk) 09:19, 29 July 2021 (UTC)
User:Smartoldie has added a substantial amount of detailed content to this article that appears to be original research. I have posted a notice on the user talk page User talk:Smartoldie. I propose to revert the edits within 24 hours if there is no response to the request for citations to support the content that has been added._Marshelec (talk) 02:57, 7 October 2025 (UTC)
After discussions with User:Smartoldie on their talk page, I have copied the content added to the article into this talk page, as a prompt for topics that could be included in the article in future, if reliable published sources can be found.
The challenges for managing the three waters in the Wellington region include the deteriorated condition of the city reticulation pipelines, in Porirua, Lower Hutt, Upper Hutt and Wellington City.
The bulk water pipelines supplying the four cities, whilst having the occasional leak are repaired quickly and due to the high pressure of these pipes, leaks are self evident where the pipes are in a residential area and will be reported by the public. Several kilometers of the Te Marua Treatment plant pipeline to the Karori reservoir complex were retrofitted with leak detection bars as part of the Wellington Regional Council’s Technical Services project to investigate mainly city reticulation. No leakage was detected in the steel welded joint pipeline. A small deliberate leak created by installing a small valve on top of an inspection port’s blank flange was set up to test the efficacy of the then model 3 (maker yet tbc) electronic listening leak detector. In the leak detection contractor’s haste to survey the pipe (they were paid by the km surveyed) the deliberate leak was missed. Upon being informed by the Pipeline Engineer that they has missed a leak, they re-surveyed the section in question and after 20 minutes, the correlator found the leak. Thus, knowing the daily flow rate, the sensitivity of the detector was physically measured and it was extremely sensitive thus proving its value beyond doubt. The Bulk Water PipelineI Enginner then changed the Pipeline Construction Standards by adding leak detection bars to steel pipelines and on steel special pieces (no standard fittings) on Ductilr Iron rubber ringed pipes. In conclusion, the failure of city reticulation systems does not apply to the Bulk Water Pipeline System, an important distinction.
It has been claimed that the deteriorated state of the three waters infrastructure is the result of 50 years of under-investment, and that large increases in rates for water services will be necessary. The cause of these leaks is due to the nature of the city reticulation systems. For example, MDPE pipe was used in Porirua and there were many failures (leaks) on relatively new pipes. The cause was poor backfilling of the trench when under construction. Plastic pipes require backfill material to be soft, eg: sand and any stones or rocks inadvertently finding their way into the trench can cause failure and leaks. Another cause of failure in Porirua City’s reticulation was and is the ongoing failure of Asbestos Cement (hereafter AC) pipes, AC pipes were destined and created by an Austrian, Dr Mazzi, but he did not forsee that over time, the pipes would absorb water, swell and ultimately fail. Being somewhat brittle, these pipes were also not very resistant to poor backfill, rocks and stones.Finally, in contradistinction to steel welded Bulk Water Pipes, which form a leak free system (when welds are properly x-rayed and pipes pressure tested, city reticulation systems use mechanical joints, either push in joints, Gibault Joints or their modern successors, sleeve joints (made by Viking Johnson in the UK and abroad and Dresser in America, primarily for oil pipelines) , all of which rely on a rubber seal. Historically, the rubber used was natural rubber which deteriorates even when not exposed to sunlight. EPDM, a synthetic rubber, is now used for these modern sleeve joints and also in gate valves as a lining to separate the valve body from the potable water, thus avoiding contamination. Other possibilities for leak causation is the use of inferior materials. For example, an air valve near a road may have a small copper pipe between the main pipe and the air valve. Constant vibration from traffic may cause the slender pipe to fail as it is connected to a relatively heavy valve, if not supported properly. Here, a stainless steel, hard material is a better design. One more and there are many more reasons for leaks is the failure to install thrust blocks on valves and bends, not a problem on an integral steel system but catastrophic for a jointed connection using rubber as on closing the valve or pressurising the bend, the pipe is subject to a force of value, cross sectional area multiplied by pressure. Such failures can rip a jointed system to pieces.
Finally, for your perusal; in Wellington, earthquakes, even small tremors, cause failures and leaks, especially in the historic cast iron pipes. These can easily crack and experience catastrophic brittle failure (impossible in steel pipelines unless the pipe is subjected to abnormally low temperatures – not really possible in New Zealand.
An earthquake mitigation and preparedness report was procured from Opus, now WSP consultants (to be confirmed) and the report led to the acquisition of spare large diameter pipes, which were deposited in two pipe dumps, one at Gear Island and the other near Grenada North on the Te Marua to Karori pipeline. The spare pipes were sealed off and buried to prevent deterioration of the tape coating. The idea was, that in the event of an earthquake, a large digger (excavator) would first uncover the pipes and then be used to transport the pipes to the location of any bursts, as roads may be unable to be used after an earthquake event. The maintenance depot at Mabey Road, Lower Hutt, contained the spare couplings required and had preparedness measures implemented, such as beds, emergency food, and most importantly, a 10,000 litre pressurised water tank to ensure constant water turnover prior to chlorination, by re-purposing a redundant surge vessel once used at the Ngaio pump station. Even the seat of government, the Beehive, only had 15,000 litres of emergency water.
In the mid 1990s, city reservoirs supplied by the Bulk Water Pipelines were retrofitted with dedicated non-return valves (rather than re-plumbing the inlet control valves to provide non-return function) to prevent water loss should the inlet pipe fracture and leak, thus draining precious, needed water. Regarding the Silversteam bridge, the original proposed scheme was to make a diversion across the Manor Park Golf Club, home to Michael Campbell incidentally) and use a new method of allowing the pipe to deflect in a trench of soft backfill. Normally, thin wall pipes require a solid backfill to reduce the working stress on the pipe; this increase in pipe wall thickness was part of the design (tbc) Now, this scheme and a new combined road/pipe bridge as a replacement of the old bridge, which had pipes joined mechanically is the plan.
