Main Sewer Line Cleaning in Fresno, CA

Fresno's hardpan is locally famous for good reason. The cemented layer in these valley soils is hard enough that the Forestiere Underground Gardens, the network of tunnels and courtyards a Sicilian immigrant excavated by hand over four decades, were cut through it with picks and shovels and stand open to this day. That is the material a sewer trench here has to get through. Hardpan sits at a fairly consistent depth, frequently right around where a lateral runs, and it usually has to be broken rather than dug, which makes excavation in this city slower and more expensive than the depth alone would suggest.

Hardpan has a second effect. Being far less permeable than the soil above it, it perches water rather than letting it drain away, so the ground around a lateral can stay saturated long after a storm, and irrigation water sits in the root zone where trees can find it.

The San Joaquin Valley also has the most serious land subsidence problem in the state. Decades of groundwater overdraft have lowered the ground surface across large areas, and satellite measurements taken for the state during the drought years recorded parts of the valley sinking at rates approaching two inches per month in the worst-affected places, with thousands of well casings destroyed and aqueducts and bridges damaged. California passed groundwater management legislation in 2014 in response. Permanent, uneven settlement of that kind pulls a rigid sewer lateral out of grade, and unlike seasonal clay movement it does not come back.

The housing runs from the Tower District and the older central neighbourhoods, with 1900s to 1930s properties on cast iron and early clay, through enormous postwar expansion carrying mid-century clay and some Orangeburg, to modern plastic in the newer suburbs.