Rose Valley Water Service Area – Summer 2025 Recap

Date of Issue: Wednesday, Oct. 7, 2025

Dear Rose Valley Water Service Area Customers,

We are reaching out to share what’s new since our last update on July 23. This update includes information on:

• Raw source water – Rose Valley Reservoir
• Pre-treatment of raw source water– Rose Valley Dam
• Treated water – Rose Valley Water Treatment Plant
• Other capital improvements
• Distribution – planned watermain flushing maintenance program

This update primarily provides information about the Rose Valley Water Service Area, but it is being sent to all subscribers including those in the separate Powers Creek Service Area, who may wish to know more. If you are unsure of your service area, please see your utility bill or call 778-797-8850 or refer to our Water Systems map, available on our website.

As part of our commitment to expand communications, information and education, monthly water data for both service areas are posted on the City’s website at westkelownacity.ca/waterquality. If you have questions about the data, please call 778-797-2246.

Raw source water – Rose Valley Reservoir

Our monitoring at the Rose Valley Reservoir indicates fluctuating levels of manganese in the raw source water for the Rose Valley Water Treatment Plant continued to occur in the summer of 2025.

As temperatures in the reservoir climbed, the heat increased the manganese levels and the amounts of organics – such as algae – in the raw source water. Manganese levels in the reservoir began exceeding the health objective in the raw source water the week of July 16. However, these fluctuations were expected, and the raw source water is being effectively pre-treated at Rose Valley Dam and Rose Valley Water Treatment Plant.

Pre-treatment of raw source water – Rose Valley Dam

The City began dosing with sodium permanganate on July 21, 2025 and the system is successfully oxidizing the dissolved manganese prior to it entering the treatment facility.

The dosing system is still in the commissioning process and staff continue to work with the project team to improve the new system. Further commissioning includes calibrating the analyzers, refining the dosage, and adding the ability to dose with potassium permanganate.

The system can remotely communicate with the Rose Valley Water Treatment Plant, so operators can adjust the treatment as conditions in the reservoir change. The dosing system was also designed to dose with either potassium permanganate, or sodium permanganate. This provides the City with flexibility to purchase liquid sodium or solid potassium chemicals based on availability and pricing.

Prior to the permanganate dosing system, the City was oxidizing manganese with chlorine so the plant could remove the manganese. This process started in May with a low chlorine dose. As manganese levels in the reservoir began rising this past summer, the chlorine dose was adjusted accordingly.

Oxidizing with permanganate has also reduced the amount of disinfection by-products compared to pre-dosing with chlorine.

Treated water – Rose Valley Water Treatment Plant

Rose Valley Water Treatment Plant remains in the commissioning phase and is performing well.

The treatment plant has been removing manganese from the source water and levels remain below the aesthetic objective (0.02 mg/L) since pre-dosing was implemented in August 2024.

Our continued monitoring shows that water leaving Rose Valley Water Treatment Plant is meeting or exceeding provincial and federal standards for drinking water and the levels of manganese and disinfection byproducts are below Health Canada’s objectives.

Other capital improvements

Aeration system

On June 10, 2025, Council directed staff to expedite and complete the installation of the Rose Valley Reservoir aeration improvements in 2025. Procurement for the aeration equipment is underway with the intent to install the equipment in 2025, weather permitting.

The system is planned to provide hypolimnetic aeration, which will prevent manganese from migrating from the sediment. It will also reduce nutrient migrations fuelling algae blooms. This is intended to be a long-term reservoir management solution that will help reduce the need to pre-oxidize and improve taste and odour in the drinking water source.

Distribution – planned watermain flushing maintenance program

The City’s planned watermain flushing maintenance program is progressing, with crews currently working in Zone RV04B – Tallus Ridge (see map).

An isolated, precautionary water quality advisory will be in effect, only within the flushing zone, while the planned maintenance program is underway.

Flushing forces high-velocity water through hydrants to remove sediment that has accumulated in the distribution system’s mains over time, prior to the current treatment processes. Any disruption or colour/turbidity should be brief and occur only while mains in the area are being flushed. If you notice colour/turbidity, do not drink the water, and run the cold tap for several minutes until clear; if water does not run clear after 10 minutes, please call us at 778-797-2246.

To see the maps and learn about recommended steps customers should take before, during and after flushing in your area, please visit westkelownacity.ca/flushing.

To help customers know more specifically where flushing will be occurring the City of West Kelowna has reduced the size of the flushing zones and is providing a schedule of flushing dates for individual streets within each zone. Staff are also posting signs at main neighbourhood entrances to more clearly state that a precautionary water quality advisory is in effect, for that specific zone, for the purposes of watermain flushing only.

Notifications – please, remain signed up to receive City news and alerts

We will continue to issue notifications to customers and post on our social media channels when flushing ends in one area and is scheduled to move to the next. Please remain signed up to receive City news and alerts, directly to your email inbox, and encourage friends, family and neighbours to do the same. Sign up at westkelownacity.ca/subscribe. Follow us on  Facebook, Instagram and X.

The City has completed flushing in Sunnyside/Pritchard including the South Boucherie, Sunnyside, Pritchard and Green Bay areas, West Kelowna Estates, Rose Valley, Boucherie Centre, West Kelowna Business Park and Lakeview Heights. Remaining flushing for Shannon Lake – Zones RV05A, B and C is expected to begin in late October 2025, subject to weather and other factors.

Hydrant uses and other factors that could temporarily discolour water

Unlike planned flushing maintenance, which we report to the public in advance, changes in velocity can occur within the distribution system from emergencies such as firefighting and watermain breaks or unauthorized hydrant use. The higher flows from these activities can also stir up accumulated sediment in the pipes and cause temporary colour in households nearest to the sudden event.