Wastewater, Earthmoving, Erosion Control



The Wastewater Treatment and Disposal program ensures proper design, construction and application of approved on-site wastewater disposal systems. Individual Wastewater Disposal System (IWDS) are systems designed for individual homes (and some commercial and business facilities) to dispose of wastes through septic tanks, leaching fields or seepage pits. Other Wastewater Treatment Systems (OWTS) are systems designed and installed to treat and dispose of sewage from a single structure or group of structures other than septic tanks together with leaching fields or seepage pits. This branch ensures that waste from these systems:

  • Do not contaminate any drinking water supply.
  • Are not accessible to insects, rodents, or other possible carriers of disease, which may come into contact with food or drinking water.
  • Do not pollute or contaminate any waters used for public or domestic water supply purposes or for recreational purposes.
  • Are not a health hazard, by being accessible to children.
  • Do not give rise to nuisances due to odor or unsightly appearance.
  • Will not violate any local laws or regulations governing water pollution or sewage disposal.

This branch is also responsible for reducing the direct and indirect discharge of untreated animal waste to state water and groundwater through use of components and practices (such as septic tanks, leach field, waste storage ponds, waste utilization, composting or other methods). A confined animal facility means a lot or facility (other than an aquatic animal production facility) where the following conditions are met:

  • Animals (other than aquatic animals) have been, are, or will be stabled or confined and fed or maintained for a total of 45 days or more in any 12-month period, and
  • Crops, vegetation forage growth, or post-harvest residues are not sustained in the normal growing season over any portion of the lot or facility.

Facilities are requested to construct and operate an Other Wastewater Treatment System (OWTS) if they contain any of the following number of head:

  • 15 or more pigs
  • 20 or more goats
  • 10 or more cattle
  • 100 or more chickens
  • OR, any confined animal facility which had been found by the Division of Environmental Quality (DEQ) to have caused, by evidence of direct or indirect discharge, in violation of the CNMI Water Quality Standards or CNMI Drinking Water Regulations.

Large confined animal facilities (more than 100 heads of pigs, 1000 chickens, or 50 cattle) may be required to meet more stringent requirements which is determined on a case-by-case basis. Runoff includes any precipitation (rain or snow) that comes into contact with any manure, litter, or bedding. Facility wastewater is water discharged in the operation of an animal facility as a result of any or all of the following: animal or poultry watering; washing, cleaning, or flushing pens, barns, manure pits, or other animal facilities; washing or spray cooling of animals; and dust control.


Residents and industries are required to submit a permit application for either Individual Wastewater Disposal Systems (IWDS) or Other Wastewater Treatment Systems (OWTS). Septic System and Wastewater Pumpers or any person engaged in the business of cleaning IWDS or disposing of the waste must also complete a Septic System and Wastewater Pumper Application. For convenience, here are the Septic Tank Requirements. Once an application is received, it is reviewed for all required data (percolation rate, daily sewage flow, system size and capacities). Staff will conduct a pre-inspection of project site to check and verify setback requirements. The permitting process is within a 30-day period upon receipt of the complete application package, including an intensive review of system plans, designs and calculations. Permits are issued for the purpose of constructing IWDS or OWTS with construction to begin within 90days of permit issuance. During construction stage of disposal system, staff will continue to monitor developments until the project has been completed. Upon final inspection by staff, a Certificate For Use (CFU) shall be issued to the permittee.


The Wastewater Treatment Rules and Regulations CR Vol. 24, No. 11, November 27, 2002 (CNMI Environmental Protection Act, Public Law 3-23, 2 CMC §§ 3101 et seq. (as amended by P.L. 11-103), 1 CMC §§ 2646 to 2649, and Public Law 11-108); Northern Mariana Islands Administrative code chapter 65-120, Wastewater Treatment and Disposal regulation; are available at the end of this article. It can also be accessed in the Permits and Regulations section of this website.