Revised on
01/08/19 10:52am
SafetyNet #

Drain Disposal Guidelines

Contact information

A. Summary

UC Davis generates over 2 million gallons of wastewater each day, primarily from restroom and dormitory sewage, but also from laboratory drains and other non-domestic wastewater sources. The wastewater is treated at the University Wastewater Treatment Plant off Old Davis Road, and then discharged either to the North Fork or the South Fork of Putah Creek.

Discharge of inappropriate materials into the sanitary sewer can damage sewer pipes, jeopardize the health of maintenance workers, and cause adverse environmental impacts. This guideline presents appropriate wastewater disposal methods on what can and cannot go down campus drains.

B. Local Limits Program

The University developed the Local Limits program to help prevent inappropriate sewer disposal. The program was designed to provide specific guidance on how to answer the question, "Can this go down the drain?" The goal of the Local Limits program is to educate users, and prevent inappropriate materials from being discharged into the sewer. The comprehensive Sewer Disposal Policy has specific sewer discharge limits for over 100 constituents of concern for easy reference. If the limit for a chemical you are interested in is not listed, please contact to ensure drain disposal is acceptable prior to pouring the solution down the drain.

C. Discharge Permits

The Regional Water Quality Control Board mandates maximum discharge limits for several materials in the campus wastewater treatment plant permit. The materials of greatest concern, and with the largest number of permit violations for the campus, are salts (measured as total dissolved solids or electrical conductivity), copper, aluminum, and cyanide. The campus community must be especially vigilant in following sewer disposal policies for these materials. The following sewer discharge limits are in place:

  • Any sewer discharges that exceed 900 umhos/cm, and any new proposed water softeners (or other water treatment devices that discharge waste brine), must be approved by Utilities (530-752-7553).
  • Adding Copper is not allowed.
  • Wastewater containing Aluminum shall not exceed 87 parts per billion.
  • Wastewater containing Cyanide shall not exceed 20 parts per billion.
  • Wastewater containing Lead shall not exceed 21 µg/l
  • Wastewater containing Iron shall not exceed 3.0 mg/l
  • Wastewater containing Methylene Chloride shall not exceed 100 µg/l
  • Wastewater containing Silver shall not exceed 1.2 µg/l
  • Wastewater containing Hexachloreothane shall not exceed 2.6 µg/l
  • No Bis(2-ethylhexyl)phthalate discharge is allowed.
  • No Tributyltin discharge is allowed.
  • No Mercury discharge is allowed.

If your waste contains any of these materials at concentrations above the local limits, please submit a pick-up request via WASTe.

Bright yellow and red sink labels are available to post on sinks to educate the campus about sewer disposal. If you have sinks that have not been labeled contact EH&S by phone (530-752-1493) or email