Why Toxic Algae Blooms Are on the Rise Across California — and Expected to Get Worse

Rising temperatures and stagnant water generally signal trouble for human life, but they make for a great environment for the bright, blue-green scum often found in lakes, rivers and reservoirs that flourishes and blooms in hot weather.

These scum blooms, known as harmful algal blooms, are natural parts of the ecosystem, but can also release toxins that sicken or even kill people and animals. They’re becoming more common as temperatures rise and water systems are starved and disrupted, threatening not only public and wildlife health, but the state’s water supply, as well as beloved recreation areas like Lake Merritt in Oakland.

Businesses That Have Been Closed Should Flush Out Water Systems

The Escondido Utilities Department worked with the Communications Department and Economic Development to develop business outreach to commercial, industrial, dining, and retail operators that have been completely closed due to the COVID-19 pandemic. 

Escondido’s Utilities Department has provided clean and safe drinking water throughout the pandemic, but water sitting in the internal plumbing of a closed building could be unsafe for drinking. Businesses that have not been occupied are being advised to flush internal plumbing systems to clear the potentially stagnant water prior to building occupancy. 

Buildings that have been occupied, even partially, during the pandemic do not need to take these steps because the plumbing in these buildings is routinely refreshed with water from the City’s water distribution system. 

Water Systems in Closed Buildings May Require Flushing and Testing

Plumbing systems in buildings closed or vacant for long periods may need to be flushed to safely remove stagnant water.

Water provided by the San Diego Water Authority and its 24 member agencies continues to meet all state and federal drinking water standards. But after water leaves the agencies’ distribution systems and enters private service connections, the water quality can deteriorate if water becomes stagnant.

Most commercial and industrial buildings have been partially occupied even during the COVID-19 shutdown, and HVAC and water systems continue to be maintained and operated even though many employees are working remotely. However, building owners and managers should take special care with plumbing systems in buildings that have been vacant or have had periods of low water use to protect the public and employees returning to work.

That’s because plumbing systems must be actively managed and maintained to prevent bacteria growth. Bacteria can flourish in pipes, fixtures and associated equipment (like fountains, cooling towers and HVAC systems) that aren’t used for several days. Schools, for example, commonly flush pipes before kids and teachers return from breaks.

Plumbers Warn Small Business Owners to Run Water Before Reopening

When small businesses are closed it means appliances haven’t been running inside; a problem that could be putting customer’s health at risk but also damaging the plumbing.