Hello summer – check the water quality grades for popular sites
Want to know where's good to swim this summer? At the start of each season, we share long-term water quality grades for our region's popular rivers, lakes, and beaches. These grades are based on water sampling results from the past five summers.
Latest results heading into the 2025-26 season
This year, 77% of Canterbury’s monitored swimming sites are suitable for contact recreation (swimming and other water-based activities) — consistent with last season.
Dr Elaine Moriarty, our acting chief scientist, explains that each summer, starting in mid-November, we monitor 52 popular freshwater sites and 47 coastal sites.
"Our teams are out weekly throughout the summer season collecting water samples and testing for faecal indicator bacteria to determine which sites are safe for everyone to enjoy," she said.
📋 Learn more about where to swim this summer on our 2025-26 report card (PDF file, 1.77MB).
Positive results at coastal sites
- 85% of Canterbury’s coastal sites (estuaries, harbours, beaches) were graded suitable for contact recreation.
- 100% of open coast beaches received grades of 'very good', 'good', or 'fair'.
- This maintains the same high standard as the 2023–24 season.
"Across Canterbury, our beaches continue to perform exceptionally well, which is fantastic news for beachgoers," Dr Moriarty said.
Mixed results for freshwater sites
- 71% of freshwater sites are suitable for recreation.
- Lake sites performed well, with 87% suitable.
- River sites showed more variability, especially in urban and agricultural areas.
✅ Examples of suitable sites:
- Ashley River Rakahuri
- Hanmer River
- Hurunui River at SH1
- Selwyn River Waikirikiri at Chamberlains Ford and Glentunnel
❌ Examples of unsuitable sites this season
- Hurunui River at SH7
- Waipara River at Boys’ Brigade swimming hole
- Waimakariri River (between highway bridges and at Thompsons Road)
- Selwyn River at Coes Ford
🆕 South Canterbury changes
- Waihī River at the Gorge improved from ‘fair’ to ‘good’.
- Pareora River, Temuka River, and Lake Alexandrina dropped from ‘fair’ to ‘poor’.
“We will continue to work with local councils and the community to identify the sources of the contamination and improve water quality at these popular recreational sites,” said Dr Moriarty.
Check water quality before you swim
As the long-term grades, which summarise the last five years, are only updated after the end of each season, weekly water sampling provides a more up-to-date picture of water quality, which can be variable.
"Canterbury has some fantastic swimming spots to cool off in over summer, and we're pleased that remains the case this season, with 77% of all monitored sites graded as suitable for contact recreation," said Dr Moriarty.
Top tips for safer swimming:
- ✅ Check LAWA first – get the latest water quality updates.
- 🌧️ Wait 48 hours after rain – runoff can carry bacteria into waterways.
- 👣 Toe test – if you can’t see your toes standing knee-deep, don’t swim.
Stay safe this summer – use LAWA’s Can I Swim Here? tool to check current water quality before jumping in.
Public health warnings
During the 2024/25 summer:
- 46 temporary warnings were issued across 34 sites:
- 28 for faecal contamination
- 18 for toxic algae
"These temporary warnings are a crucial part of keeping the public safe," Dr Moriarty said. "We monitor not just for bacteria but also conduct surveys for toxic algae at freshwater sites where blooms may pose health risks."
Toxic algae (also called cyanobacteria) is a naturally occurring algae with the potential to bloom, producing toxins that can harm or even kill dogs, people and other animals.
River, marine and lake health warnings: Check our health warnings pages to see sites with current alerts.
Investigating harbour contamination
We're continuing our multi-year investigation into the sources of faecal contamination in Whakaraupō Lyttelton Harbour, in partnership with Christchurch City Council (CCC) and other local organisations. Together, we're working to identify and address pollution sources to protect the harbour's health.
Read CCC's latest news article: All eyes on Lyttelton water
"This season's investigations have identified several inflow points – streams and stormwater outfalls – that contribute to contamination, and we're working with our partners to address these sources,” Dr Moriarty explained.
Developing a predictive water quality model
Our science team is currently developing a predictive water quality model that will give swimmers and other harbour users real-time information about water quality at popular sites around Whakaraupō Lyttelton and Akaroa Harbours. We anticipate that the model will be ready for use for the upcoming swimming season.
🔍 Explore how our predictive water quality model works and see what it means for your favourite swimming spots.