Burned homes kept drawing water.The hydrants ran dry.
Photo: CAL FIRE, Jan 2025 / public domain.jpg){kind=link}
On the first night of the Palisades Fire, thousands of destroyed houses left their water lines open while firefighters needed every gallon. Replay those 24 hours on real data, then see what changes when each open line shuts itself off.
Palisades hydrants lost water, mostly at higher elevations.1
All three hillside water tanks ran dry, one after another.2
Leaking connections at burned properties that LADWP crews shut off by hand, two days later.3
Real data: structure locations and damage (CAL FIRE), hydrant locations (LADWP, LA County), terrain (USGS). Computed by our model: every pressure, tank level, leak and burn time shown here. Cyan shading marks pressure zones in served areas; dashed cyan lines are the elevations where one zone hands over to the next.
How to read it
Each zone's water level is set by its tank. A hydrant's pressure is how far that level sits above it: every 2.3 ft of height is 1 psi.
When a tank empties, the level drops. Once it falls below a hydrant, that hydrant is dry.
A valve that closes when the house is gone
Firefighters can't shut off thousands of water lines in the middle of a firestorm. The house has to do it for them. Interactive mechanism →
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Step 1 / Armed
Water pressure holds it open
A thin, fragile pipe loop wraps the house and stays full of pressurized water. That pressure holds a spring-loaded gate up, out of the service line.
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Step 2 / Loop breaks
Lose the loop, the spring shuts it
When fire melts the loop or the house collapses onto it, the pressure is gone and the spring drives the gate down. No power, no electronics in the shutoff path. Hosing the house does not trip it.
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Step 3 / Reset
Repair the loop, pull the handle
Cap or repair the loop, then pull the reset handle. Pressure rebuilds, re-cocks the spring, and holds the gate open again. See it move →
More valves, and the hydrants come back
The same 24 hours, run again with a different share of homes fitted with a valve. In the model, firefighting alone empties the first two tanks either way. What the valves change is the long night after: with the leaks gone, the pumps catch up and hydrants get their pressure back. Numbers cover the mapped area.
| Homes with a valve | Hydrants < 20 psi next morning | Lost to leaks, 24 h |
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How we built this
Every dot on the map is a real structure from CAL FIRE's post-fire damage inspection, and every hydrant is a real LADWP or LA County hydrant. We estimated when the fire reached each structure by georeferencing CAL FIRE's progression map, and assigned each point a pressure zone from its ground elevation.
The water model is small on purpose. Destroyed homes leak in proportion to the square root of local pressure. Firefighting draws water where the fire is. Pumps lift water to three hillside tanks and slow down as their intake pressure falls. We tuned it once so the "What happened" run matches the public record, then ran the valve scenarios with the same settings.
It is a model, not a reconstruction. The biggest unknown is how much water one destroyed house leaks; no public figure exists, so it is a calibrated assumption.
| Check against the record | Reported | Model |
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Model settings
What the model leaves out
Pipe-by-pipe hydraulics (LADWP pipe data is not public), exact pressure-zone boundaries, pressure-reducing valves, residents' sprinklers and hoses, water tenders, and the crews' manual shut-offs. The map covers the Pacific Palisades core, Marquez Knolls and Palisades Highlands, not the whole fire.
Try other values for the three biggest assumptions with the controls next to the map. Back to the replay
Share of hydrants below 20 psi the next morning (10:30 AM, Jan 8). Rows: leak from one destroyed home. Columns: share of homes with a valve. Uses your current firefighting and pump settings; outlined cell = your current leak setting and the valve share selected in the replay.
Computing…
Computing…
Computing…
- Mayor Karen Bass and LADWP, Jan 8, 2025, as reported in this fact check; LADWP statement via FOX 11.
- Tank times from LADWP, reported by ABC7. Tank capacities from the LADWP Palisades Fire Water System Preliminary Report (Jul 3, 2025).
- About 4,800 leaking access points shut off: LADWP preliminary report (above). Crews could not return for two days: ABC7 (above).
- How burned homes drain the system, the 37,000 gpm trunk limit and the 6:30 PM low-pressure reports: California Natural Resources Agency memo (Nov 2025).
- Structures and damage: CAL FIRE DINS, 2025 Palisades. Fire progression: CAL FIRE Incident Management Team 2 progression map, with the band-date correction noted by The Lookout.
- Hydrants: LADWP Fire Hydrants (LA GeoHub) and LA County Fire hydrants. Terrain: USGS 3DEP 1/3 arc-second elevation.
- Header photo: homes burning along the coast during the Palisades Fire, CAL FIRE, January 2025, via Wikimedia Commons (marked public domain).