Water Quality

Many residents notice a pink, orange, or reddish film forming in toilets, showers, tubs, sink drains, or on tile grout.

In most cases, this is not caused by the City's drinking water. The discoloration is commonly caused by Serratia marcescens, a naturally occurring airborne bacteria that thrives in moist environments. It feeds on soap residue, shampoo deposits, and other organic materials commonly found in bathrooms.

Is it harmful?
Generally, no. The pink film is primarily a cosmetic issue and is not considered a drinking water quality concern.

How can I prevent it?

• Clean bathroom surfaces regularly
• Keep showers, tubs, and sinks as dry as possible
• Use exhaust fans to reduce humidity
• Remove soap and shampoo residue from surfaces

Cloudy or milky water is often caused by tiny air bubbles trapped in the water.

This can occur due to temperature changes, watermain maintenance activities, or pressure fluctuations within the distribution system.

How can I tell if it's air?
Fill a clear glass with water and let it sit for a few minutes. If the water clears from the bottom upward, the cloudiness is caused by air bubbles and is completely harmless.

Changes in taste or odor can occur for several reasons, including:

• Seasonal changes in source water
• Temperature fluctuations
• Plumbing conditions within the home
• Temporary maintenance work on the water system

Nanaimo's drinking water is routinely tested to ensure it remains safe and meets all applicable water quality standards.

Chlorine is used to disinfect drinking water and protect public health by eliminating potentially harmful microorganisms.

A small amount of chlorine remains in the water after treatment. This is called a chlorine residual and helps maintain water quality as water travels through the distribution system to homes and businesses.

The City carefully monitors chlorine levels to ensure they remain within provincial drinking water guidelines.

Lead is generally not found in Nanaimo's source water. When lead is detected in drinking water, it is typically the result of corrosion in older plumbing materials, fixtures, or service connections.

To help minimize potential exposure:

• Flush your taps: Run cold water for at least 30 seconds before using it for drinking or cooking if the water has been sitting unused for several hours.
• Use a certified filter: Choose a filter that is certified for lead reduction and follow the manufacturer's maintenance instructions.
• Use cold water only: Do not use hot tap water for drinking, cooking, or preparing infant formula, as hot water can increase the amount of lead that dissolves into water.

View the latest testing results: 2025 Lead Testing Results

AC pipes were commonly installed across North America from the late 1940s to early 1970s. Nanaimo has been proactively replacing these pipes since the mid‑1990s, upgrading 4–5 km per year through our Asset Management Program.

The City of Nanaimo’s drinking water meets and exceeds all senior government regulations. All water samples collected to date, including those taken from areas served by AC pipes and following recent main break events, have tested negative or non‑detectable for asbestos.

View the latest testing results: 2024 Asbestos Cement Testing Results

PFAS are synthetic chemicals used in products like non-stick cookware and firefighting foam. They persist in the environment and may post health risks.

You can use filters to remove them such as activated carbon or reverse osmosis systems.

The City has independently undertaken PFAS testing initiatives, as PFAS remains a topic of significant interest and discussion among water utilities across North America. All correspondence and testing results related to PFAS are public records and have been published on the City's website.

Our raw water source, prior to treatment, is located within a protected watershed and is not impacted by wastewater discharges or other known human activities that could introduce PFAS into the water supply. The City's PFAS monitoring program is conducted to confirm the integrity of our source water and to demonstrate our commitment to responsible drinking water management and stewardship.

View the latest testing results: 2025 PFAS Testing Results

Watermain flushing is a routine maintenance activity that helps maintain water quality throughout the distribution system.

Flushing helps to:

• Remove sediment buildup
• Improve water clarity
• Maintain proper water flow
• Ensure hydrants and valves operate correctly

Will flushing affect my water?
You may notice temporary discoloration, cloudiness, or pressure fluctuations following flushing activities. If this occurs, run a cold water tap for several minutes until the water clears.

For more information regarding water main flushing, see our Water Main Flushing page.