24H Mold Inspection of Altadena

John Woodbury planted the deodar cedars along Santa Rosa Avenue in 1885, and the lane has been lit every December since 1920 — the oldest large-scale outdoor Christmas lighting display in the country and a designated California historical landmark. The houses beneath them sit under a canopy that never fully releases a storm: shaded roof planes, north walls that stay damp for days, and needle litter that packs roof valleys, gutters, and area drains until water backs up under the shingle course instead of running off. Root systems a century and a half old also run beneath foundations and drain lines here, and the slow displacement they cause opens the paths that water follows.

The Davies Memorial Building at Farnsworth Park went up in 1934, built by Depression-era work crews out of arroyo stone hauled from the washes below — the same rounded cobble that appears across this part of town as foundation stem walls, chimneys, porch piers, and terraced garden walls. Cobble laid up at grade carries no damp-proof course between the masonry and the wood sill plate resting on it, so ground moisture climbs the stone and arrives directly at framing. Irregular rounded stone also leaves wide mortar joints that erode faster than the rock does, and once a joint opens on an uphill-facing wall it takes water straight into the crawl space behind it.

Chaney Trail climbs northwest out of town toward Millard Canyon and the ruins of the Mount Lowe Railway, whose Echo Mountain resort burned in 1900 and whose right-of-way was abandoned for good after the floods of 1938. The corridor is steep, narrow, and single-access, and the parcels along it sit on canyon walls rather than on the alluvial flat below. Water here arrives as concentrated flow off rock rather than as sheet flow across a yard, so it reaches a foundation at one point and with force behind it. Houses cut into these slopes rely on retaining walls, subdrains, and daylighted drain lines that silt up quietly, and rooms set partly below grade take the consequences first.

Abbot Kinney ran a citrus ranch on this mesa in the 1880s and coined the name Kinneloa from his own surname, years before the canals that made him famous elsewhere. What survives is a pattern of large parcels, private roads, long driveways, and houses set well back from any public main, much of it built out from the 1950s onward. Distance is the operative fact. Some properties here sit on septic rather than sewer, and supply runs measured in hundreds of feet mean a slow break loses water into the ground for months with no meter reading and no neighbor close enough to notice the wet ground.

Las Flores Canyon drains straight into this part of town, and the county debris basin at its mouth is what stands between a burned watershed and the streets below — one of a chain of basins built across these foothills after the floods of the 1930s showed what an unvegetated slope does in a storm. A basin protects only to the extent it has been cleaned out since the last event, and the storm that fills it is not always the one that overtops it. On the residential side, older housing here sits on raised foundations with crawl space vents set low to grade, which is exactly the elevation that takes water first when a street runs.