City of Modesto Compost Facility

The City of Modesto Compost Facility was first established in 1997 to comply with AB 939 legislation which required California jurisdictions to implement programs to divert 50 percent of the waste stream materials from landfills. Composting programs not only helps the City meet this requirement, but also produces beneficial and safe land application product. 

Senate Bill (SB 1383) is requires a 75% waste stream diversion and specifically targeting the removal of methane producing organics (residential and commercial food scraps) out of the landfills.

What is Compost

Compost is an organic soil conditioner created by decomposing organic matter (yard waste and tree trimmings, brush, leaves, paper waste and food scraps, etc.) under controlled conditions. Compost improves water-holding capacity, soil structure and porosity creating a better plant root environment. The various applications may include soil amendment, top dressing, mulch, erosion control and an overall plant support component.

It is very important that residents and businesses only place approved green container items in the green organic waste container. Our staff takes great effort in educating the public, checking containers and removing contamination before processing into a finished product.

The compost Facility is Organic Materials Review Institute (OMRI) listed and produces high quality compost and sells it at bargain rates. 

Our Process 

The compost facility receives approximately 200 tons of community organic waste (paper, cardboard, food scraps, grass clippings, leaves, brush and tree trimmings) each day. Green and food waste materials are high in nitrogen and are mixed with chipped branches to add carbon content. After grinding, the mixed materials are placed into rows (windrows) and further processed by watering and turning (aeration). The internal row temperatures range from 132 to 150 degrees which kills weed seeds and bacteria. After about three to five months, the result is a rich-dark-humus-like product ready for use.

Testing & Assurance Program 

The City of Modesto's compost is laboratory tested and qualified for sale per the standards set by CalRecycle. Modesto's Clean Green Compost is also listed by the Organic Materials Review Institute (OMRI).