Water quality
The table below provides an overall overview of the water quality of the basin for the 2026 season.
The City of Québec conducts water quality analyses and monitoring several times a week at the Port of Québec’s harbour swimming area. Water samples are collected, analyzed by the City’s laboratories, and the results are forwarded as soon as they become available.
The minimum delay between sample collection and the release of results is 24 hours. The result displayed in light blue is the most recent one compiled by L’Oasis du Port de Québec.
As throughout the province of Québec, water quality ratings are based on bacteriological quality. This rating is calculated according to the number of E. coli bacteria per 100 ml of water, following the classification system developed by Québec’s Ministry of the Environment. After each test, a rating is assigned: Grade A (excellent), B (good), C (acceptable), or D (contaminated).
Visit the Press Room section to read articles from the Organisme des bassins versants de la Capitale regarding water quality.
To learn more about the water quality of the Louise Basin, consult the analyses published by the City of Québec.
Summer 2026 Analyses
Sampling date | E. coli Result (CFU/100 ML)* | Rating for swimming |
|---|---|---|
| 2026/06/10 | 9 | A |
| 2026/06/15 | 13 | A |
| 2026/06/17 | 26 | B |
| 2026/06/18 | 58 | B |
| 2026/06/22 | 25 | B |
| 2026/06/23 | 25 | B |
| 2026/06/25 | 18 | A |
| 2026/06/29 | 46 | B |
| 2026/06/30 | 12 | A |
| 2026/07/02 | 14 | A |
| 20026/07/06 | 21 | B |
| 2026/07/08 | 8 | A |
| 2026/07/09 | 69 | B |
| 2026/07/13 | 26 | B |
| 2026/07/15 | 65 | B |
| 2026/07/16 | 925 | D |
| 2026/07/17 | 46 | B |
| 2026/07/18 | 47 | B |
Proximity to the Marina
We often receive questions regarding the proximity of the Marina to the Oasis harbour bath and the impact on water quality. In the document below, you will find answers to numerous questions concerning the presence of recreational boats nearby and the regulations to which users of the Port of Québec Marina must comply.
Visit the Press Room section to read articles from the Capitale Watershed Organization on water quality.
