What is a sump?
Oil drilling in the Santa Maria Valley historically involved holding areas or depressions in the ground known as sumps used to contain water, drilling mud, and oily soil, during the drilling process. These sumps were eventually covered with soil and may contain miscellaneous debris. Most of the sumps in the Santa Maria Valley remain on open land, while some are located in, or near, areas that have been developed for business and residential uses. Many of these sumps have since been removed while others remain in the ground.
