Ipswich Tap Water Quality 2026: Mount Crosby, Chloramine, the January 2025 Taste Event and pH Upgrade

8 min read

Ipswich sits at a nexus of two water quality considerations that directly affect filtration decisions. First, it is on the chloramine-disinfected SEQ Water Grid — meaning standard carbon filters don’t address the primary disinfectant. Second, the Mount Crosby treatment plant that serves Ipswich is the same plant that produced the MIB/geosmin earthy taste event in January 2025 that affected residents across Brisbane, Ipswich, Logan, and Redlands. Both issues are addressed by catalytic carbon or reverse osmosis filtration, but understanding both helps explain why the right filter matters more in Ipswich than most people assume.

Where Ipswich water comes from

Ipswich is served by Seqwater’s South East Queensland Water Supply System, with treatment at Mount Crosby Water Treatment Plants (Eastbank and Westbank) on the Brisbane River. The primary source is Wivenhoe Dam — which holds approximately 1,165 GL at full capacity and supplies over 50% of SEQ’s drinking water. The Mt Crosby plants draw raw water from the Brisbane River downstream of Wivenhoe, treating it through coagulation, flocculation, filtration, and chloramine disinfection before distribution via Urban Utilities’ network across Ipswich, Brisbane, Lockyer Valley, Somerset, and Scenic Rim.

The Mt Crosby catchment draws from the Brisbane River, which passes through both protected mountain country (D’Aguilar Range) and areas with some agricultural and land use activity in the upper sections. This is one reason why PFAS has been detected at Mt Crosby — at 36 ppt PFOA, below ADWG limits but measurably present.

The January 2025 MIB/geosmin event — what happened

In January 2025, Seqwater notified residents across Brisbane, Ipswich, Logan, and Redlands of a temporary change in the taste and smell of tap water. The cause: elevated MIB (Methyl-Isoborneol) and geosmin compounds in the raw water entering Mount Crosby Water Treatment Plants, following warm, wet weather conditions that stimulated algal growth in Wivenhoe Dam. These compounds are the same ones responsible for earthy or muddy flavours in freshwater fish. They are safe at any detectable concentration but are perceptible to human taste at very low levels (5-15 ng/L).

Seqwater managed the event by releasing additional water from Wivenhoe Dam to dilute and turn over the affected raw water. The water remained safe throughout. Activated carbon filtration at the point of use effectively removes both MIB and geosmin — households with catalytic carbon filters would have been largely shielded from the taste impact during this event.

The April 2026 pH upgrade

Seqwater is currently enhancing treatment processes at Mount Crosby and North Pine Water Treatment Plants, with completion expected in late April 2026. The key change: pH will be increased from approximately 7.8 to 8.4. The purpose is to improve the stability and effectiveness of chloramine disinfection as it travels through the distribution network — a higher pH maintains chloramine concentration more consistently, reducing taste and odour impacts from disinfectant breakdown in warmer weather. Ipswich residents are expected to notice no significant change to taste from this upgrade, but the treatment process will be more stable year-round, particularly during summer.

Ipswich water quality data

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Frequently Asked Questions

Safe to drink?

Yes — all ADWG guidelines met. PFAS at Mt Crosby (36 ppt PFOA) well below updated limits.

Chloramine?

Yes. SEQ Water Grid. Standard carbon insufficient. Catalytic carbon or RO required.

Jan 2025 earthy taste?

MIB/geosmin algal compounds from Wivenhoe Dam algae. Safe but unpleasant. Carbon filtration removes both compounds.