Phoenix Lake’s Fall 2026 Plan: Creating Room for Early Winter Runoff
By Matthew Martinez, Founder, CEO & Managing Broker, Diamond Real Estate Group. California DRE #01869679.
A reservoir’s visible water level can tell different stories depending on the season and its operating purpose. Ahead of winter, creating additional empty space may be a deliberate way to receive storm runoff. That is the idea behind a new Phoenix Lake effort announced by Marin County and Marin Water in October 2026.
For buyers considering Ross and the nearby valley communities, the announcement adds current context to the relationship between the watershed, the reservoir and downstream creeks. It is an operating plan for the coming season, with decisions tied to actual conditions.
What the agencies announced
The October 22, 2026 County announcement describes lowering Phoenix Lake before winter to create more space for stormwater. The intended benefit is moderation of downstream flows during early winter storms, potentially reducing creek levels and flood risk in Ross and San Anselmo.
The announced schedule anticipated pumping beginning October 26 after pump modifications, with operations potentially continuing into mid-November. Marin Water retains the operating decisions, including when to stop, guided by weather, water quality and its drinking-water responsibilities. Those dates describe the announced plan; they do not confirm that a particular pumping milestone occurred.
Empty storage is useful only in relation to the storm
The operating idea is straightforward: a reservoir with available space can receive some inflow before that water continues downstream. Timing matters. The initial level, the sequence of storms and decisions about operations all affect how much room remains when runoff arrives.
That is why the County describes a potential contribution to early-season preparedness rather than a universal solution. Additional storage can have a useful role without eliminating flooding. A household should not interpret the announcement as a reason to abandon the preparations it would otherwise make for its own location.
A regional storage total answers another question
Marin Water’s Water Watch page reports combined storage across seven reservoirs, including Phoenix Lake. Its October 21, 2026 table lists 63,162 acre-feet, or 79.39% of total capacity, across that system. The same page provides historical comparisons and individual reservoir data links.
A system-wide percentage is useful water-supply context. It does not describe how much space is available in Phoenix Lake at a later moment or quantify a particular home’s flood exposure. The combined storage figure and the local operating plan have different boundaries, even though both concern water.
Three scales belong in a Ross home search
The watershed scale explains where runoff comes from and the public measures being considered. The neighborhood scale includes the streets, creek reaches and access routes around a home. The property scale includes elevation, drainage, buildings and other site conditions.
Keeping those scales visible makes the public announcement more useful. A buyer can follow the reservoir effort as part of the wider preparedness story while still examining the actual home and its route to everyday destinations. A public operating change does not replace address-specific flood information or an insurer’s terms.
Follow what happens after the announcement
The next useful information is operational: what the agencies report about the effort, when it concludes and how the season develops. The County has explicitly left the decisions with Marin Water rather than announcing a fixed drawdown outcome independent of conditions.
That flexibility is part of the plan’s substance. It connects flood-risk objectives with drinking-water responsibilities and observed weather. Understanding the arrangement is more informative than treating a low lake level as automatically good or bad.
Explore real estate and home for sale in Ross and the nearby San Anselmo community guide. Contact Diamond to place the public watershed context alongside the home locations you are considering.
Sources checked October 28, 2026. Pumping dates are the October 22 announced schedule, not independently verified operating results. Regional storage data are dated October 21; no parcel-specific flood reduction is calculated here.
