Aug 19, 2025 - Due to ongoing rainfall deficits and prolonged heat waves, the Rideau Valley Water Response Team has declared a Level 3 Low Water Advisory for the Rideau Valley Watershed after officials met to discuss conditions on Monday, August 18, 2025.
Level 3 conditions are triggered when rainfall deficits fall below 40% of the long-term average and/or when streamflows decline to severe low-water thresholds (typically below the 10-year return period low flow).
A Level-3 low water advisory is not a declaration of an emergency, but an indicator of significant dry conditions and impacts observed across the Rideau Valley watershed.
Current Conditions
Rainfall over the past several months has been highly variable, but overall conditions remain significantly below normal. To date, the Ottawa region has recorded 22 days with temperatures above 30 °C, further contributing to drought impacts. Looking ahead, the 7-day weather forecast shows possible minor rainfall of 10-15 mm through the weekend, and day-time temperature highs ranging from 20C to 30C across the region.
Rainfall
- 90-day totals across the watershed are 50–70% of the long-term average for this time of year
- 30-day totals are of particular concern, with most areas receiving less than 40% of normal rainfall
Streamflows
- Flows are reduced significantly across all Rideau Valley subwatersheds
- Flows on the Jock River are approaching the 1:20 year return period low flow, and have fallen to less than 30% of the typical summer low flow
Lake & Reservoir Levels
Parks Canada staff continue to closely monitor water levels throughout the Rideau Canal system. The drawdown of reservoir lakes in the Tay River and Upper Rideau subwatersheds is being carried out at the minimal levels required to maintain navigation along the Rideau Canal. Currently, water levels in the reservoir lakes (Bob’s Lake and Wolfe Lake) and the navigation lakes (Upper Rideau Lake and Big Rideau Lake) are below normal and are expected to decline further. Levels on the Rideau Canal system are currently being maintained within navigable range.
Recommended Actions
Ongoing drought conditions are placing increased pressure on both surface water and groundwater supplies, making water conservation essential. Residents and businesses across the Rideau Valley watershed are strongly encouraged to reduce their overall water use and suspend non-essential water activities until natural supplies begin to recover.
Private Wells
Residents relying on groundwater wells are urged to use water responsibly to help protect the aquifers on which they depend. Residents experiencing well water supply issues are encouraged to reach out to the Ontario Ministry of the Environment, Conservation and Parks “Wells Help Desk” (Wells on your property | ontario.ca) for guidance. If direct intervention is required, residents should contact a licensed well contractor for assistance.
Municipal Systems
Residents connected to municipal water supplies should monitor their municipality’s official channels for updates on water use restrictions.
Urban Ottawa
Residents served by the City of Ottawa’s central drinking water system are not subject to the same water supply pressures, as this system draws from the Ottawa River. However, conservation measures are still strongly encouraged to reduce overall demand and to support broader watershed resiliency.
General Advisories
All residents are encouraged to follow municipal updates for guidance on water conservation, water source conditions, and information on fire bans, as dry groundcover and vegetation have increased fire risk.
Permit Holders
Holders of Permits to Take Water from surface or groundwater sources are strongly encouraged to reduce withdrawals wherever possible. During low flow conditions, large surface water takings can significantly impact local water availability.
To better understand local conditions, landowners, businesses, and industries are encouraged to contact Isabelle Maltais by email (
Conservation Authority staff continue to monitor conditions and communicate with water managers throughout the watershed. Updates to this message will be issued as conditions warrant.
More resources:
- Ministry of Environment, Conservation and Parks - Wells Help Desk: https://www.ontario.ca/page/wells-your-property#section-4
- Ministry of Environment, Conservation and Parks – Find a Licensed Well Contractor: https://www.ontario.ca/page/find-licenced-well-contractors
- Ministry of Environment, Conservation and Parks – Managing Your Water Well In Times Of Water Shortage: https://www.ontario.ca/page/managing-your-water-well-times-water-shortage
- Ontario’s Low Water Response program: https://www.ontario.ca/page/low-water-response-program.
- RVCA website: www.rvca.caHourly and daily streamflows and water levels: https://www.rvca.ca/watershed-monitoring-reporting/reporting/streamflow-water-levels .
For more information, contact:
Isabelle Maltais
Director, Watershed Science & Engineering
1-800-267-3504 ext. 1165
"Rideau Valley Conservation Authority is a partnership of municipalities within the Rideau Valley watershed created under the Conservation Authorities Act to deliver a range of programs in watershed management and natural resource conservation."
RVCA Watershed Low Water Conditions Statements:
LEVEL I: There is minor concern. 80% to 60% of long-term average precipitation for 540 day and/or 90 day precipitation totals and/or 7-day average streamflows are less than the 5-year return period low flow.
LEVEL III: There is a failure of the water supply to meet demand. Less than 40% of long-term average precipitation for 540, 90 and/or 30 day precipitation totals and/or 7-day average streamflows are less than the 10-year return period low flow.
LEVEL II: There is a potentially serious problem pending. 60% to 40% of long-term average precipitation for 540, 90 and/or 30 day precipitation totals and/or 7-day average streamflows are less than the 10-year return period low flow.
