Where Thagoona’s
tap water comes from.
Homes in the built-up parts of Thagoona are on the Urban Utilities network, supplied from Seqwater’s Mt Crosby plants; many of the larger blocks run on rainwater tanks and bores instead. The chain is the same for every connected home in the city: water released from Wivenhoe Dam travels down the Mid Brisbane River to Mt Crosby, where Seqwater’s East Bank and West Bank plants treat it, and Urban Utilities pumps it through its Ipswich reservoirs to your meter. Seqwater publishes a report on the City of Ipswich zone every month; the headline figures are in the table below.
Two things are added on purpose. The disinfectant is chloramine rather than plain chlorine, which holds a residual over the long mains out to Thagoona and is the reason a standard carbon jug does less than people expect. Fluoride is dosed to a target of 0.8 mg/L under Queensland law. Both matter to fish keepers, who need to neutralise the chloramine, and to anyone on home dialysis, who should talk to their unit about filtration.
Tank water in Thagoona is a different product altogether. Rainwater is soft and slightly acidic, it carries whatever is on the roof, and nobody treats or tests it but the owner. Queensland Health’s advice is a first-flush diverter on the downpipe, clean gutters, a sealed tank with screened inlets, and treatment before it is used for drinking. Bore water needs a laboratory test before anything else, because its chemistry varies from one bore to the next.
Mineral spike after heavy rain, 20 November 2024. Treated water from the Mt Crosby plants recorded total dissolved solids of 700 and 730 mg/L (guideline 600), chloride of 270 and 300 mg/L (guideline 250) and hardness of 250 mg/L (guideline 200) after a significant rainfall event pushed natural mineral concentrations up in the Mid Brisbane River. Five aesthetic guideline exceedances, no health exceedance. Seqwater Drinking Water Service Annual Report 2024–25
How hard is the water in Thagoona?
Network water here is moderately hard: 80–115 mg/L as CaCO₃, against an aesthetic guideline of 200 mg/L, and it spiked to 250 mg/L in November 2024 after heavy rain washed minerals into the Mid Brisbane River. In practice that means scale on kettles, shower screens and, most expensively, on hot water elements and heat exchangers. It is why a hot water system in Thagoona benefits from scale protection on its feed, and why a whole-house softener is usually more than the water justifies. Hot water systems in Thagoona ↗
The pH is going up
Seqwater is lifting the pH of water leaving Mt Crosby from about 7.8 to a target of 8.4 from mid-August 2026, to extend disinfection in warm months, raise alkalinity and reduce corrosion in the network. The change covers Brisbane, Ipswich, Logan, Moreton Bay and parts of the Scenic Rim. For Thagoona homes that is good news for copper pipes and brass fittings, which corrode less in slightly more alkaline water, and a small nudge towards scale in hot water systems. Fish keepers will want to re-check their tank water after the change.
What the pipes in Thagoona add
Acreage plumbing in Thagoona means long service lines, a pressure pump and, for many properties, a tank between the roof and the tap. Each adds somewhere for sediment to settle and biofilm to grow, and a pump that cycles constantly is usually reporting a leak somewhere in that run. Bore water brings its own chemistry: often hard, sometimes high in iron or manganese, and always worth a laboratory test before it is treated.
The 2021 Census counted 356 private dwellings in Thagoona, 100% of them separate houses. About 14% of households rent; the rest own the plumbing between the meter and the tap outright, which is where most of what follows applies.
The Bremer River: where Thagoona’s water goes
The Bremer rises near Rosewood and Warrill Creek, runs through the centre of Ipswich and meets the Brisbane River at Barellan Point. Bundamba, Deebing, Ironpot, Western and Warrill creeks all drain into it. Most of the City of Ipswich sits in this catchment. Thagoona’s stormwater reaches the Bremer River and Western Creek.
Healthy Land & Water rated the Bremer River catchment “Poor” for environmental condition in the 2025 Report Card, with social and economic benefits rated very high. An independent Griffith University review published in February 2021 found the Bremer receives contaminants from four sewage treatment plants, a former coal mine, an abattoir and a power station, and that its water quality had not improved in 20 years. Council's Waterway Health Strategy and Habitat Connections program are the long-term response; the Report Card is the scorecard. 2025 Report Card ↗
The Queensland Government publishes live readings from stream gauges in the catchment. The nearest to Thagoona:
Where the wastewater goes
Thagoona is largely unsewered. Wastewater goes to a septic tank or an on-site treatment system on each block, and where those fail, the nutrients and bacteria go into the soil, the nearest gully and the Bremer River. Council regulates on-site systems and some work on them needs a licensed installer. If you have a bore as well as a septic system, the distance between the two is the first thing to check.
Sources: Seqwater monthly water quality report, City of Ipswich zone · Seqwater Drinking Water Service Annual Report 2024–25 · Seqwater: pH level of drinking water enhanced in parts of South East Queensland · Urban Utilities: Water hardness · Healthy Land & Water Report Card 2025: Key Messages & Catchment Summaries · Water Monitoring Information Portal · ABS 2021 Census QuickStats. Figures are for the City of Ipswich supply zone; Seqwater and Urban Utilities do not publish results by suburb. Housing descriptions are general observations, not a survey of any individual property. Data last updated 2026-09-16.