Septic Tank Cleaning

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Water Quality Certifications
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Licensure of Commercial Septic Tank Cleaners (CSTC)

Licensing Requirements

  • Rules - Septic tanks in Iowa must be pumped out only by a licensed commercial septic tank cleaner (pumper), which is a person or firm licensed by the DNR to clean septic tanks. The CSTC licensing requirements are in Iowa Administrative Code (IAC) 567 Chapter 68, "Commercial Septic Tank Cleaners".
  • Enforcement - Local County Environmental Health Departments (County Sanitarians) are responsible for enforcing the licensing requirements in Chapter 68 relating to the cleaning of private waste facilities and disposal of waste from such facilities.
  • Recordkeeping - Commercial septic tank cleaners must record the location of all cleaned PSDSs or toilet units, the method of septage or waste disposal, and the volume of septage or waste disposed of for each trip. These records shall be maintained for five years and shall be made available upon request to the local County Environmental Health Department or DNR staff.
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CSTC License Forms

  • CSTC licenses must be renewed annually.  The DNR mails out renewal applications in May of each year.
  • The renewal application fee is $150 per year for the first registered vehicle and $50 for each additional vehicle, plus  a fee of $7 per 1,000 gallons of septage to be land applied per year. Land application fees shall be based on the previous year’s records. 
  • To submit a NEW application for a license (NOT an annual renewal), use the following form:
  • To update existing license information (change name or address, add or remove vehicles, etc.), use the following form:
    • 542-2008 - Commercial Septic Tank Cleaner - Alteration Form
    • There are no fees associated with a business owner or address change or the addition of new disposal sites.
    • There is an alteration fee of $50 per new vehicle, and those who are adding one or more land application sites and who have NOT previously land applied septage must submit a prorated fee of $300. 

Currently Licensed Commercial Septic Tank Cleaners (Pumpers)

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Septic Tank Basics

Private sewage disposal systems (PSDS, or onsite systems) normally include two parts: a septic tank, the first component, followed by a secondary wastewater treatment component, such as a soil absorption leach field.

A normally functioning septic tank provides primary treatment of wastewater by acting as a settling chamber that allows wastewater to separate naturally into three distinct layers before liquid flows out of the tank. 

  • First, solid particles settle to the bottom of the tank to form a layer of sludge, and some solids are digested by anaerobic bacteria.
  • Second, greases and fats float to the top of the wastewater in the tank and form a second (top) layer, or scum layer.
  • Third, a clearer layer of liquid wastewater develops in the middle of the tank, between the sludge layer at the bottom and the scum layer at the top. The middle liquid layer of wastewater eventually flows out of the tank to the secondary treatment component (usually the final treatment component) of the system.

With normal contributions to the system, sludge builds up at the bottom of the septic tank over time despite the anaerobic digestion of some solids, and the scum layer on top of the wastewater continues to grow thicker. The continual growth of the two layers--the sludge at the bottom and the scum at the top--reduces the storage capacity of the tank and shrinks the middle liquid layer of wastewater. As this happens, wastewater flows more rapidly through the tank, which means there is less time to settle out solids and separate scum from the liquid. 

Unless there is adequate space in the septic tank for wastewater to separate into layers, solids and scum will float out of the tank and into the secondary treatment component of the system. Eventually, the secondary treatment component will clog and the entire system will fail.

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Why Septic Tank Cleaning is Needed

To ensure the long term functioning of a PSDS, the septic tank should be pumped out every 3 to 5 years, given normal household water usage. Cleaning the tank by pumping helps prevent sludge and scum from flowing out of the septic tank and into the secondary treatment system.

Proper tank cleaning refers only to removing all the solids and scum from the tank by pumping, not by any other means. Adding septic tank "additives" to a system is not a substitute for tank pumping and may harm the system if it causes solids to become suspended and flow into the secondary treatment component. It is also not necessary to add bacterial additives to a septic tank after tank pumping, since there is sufficient bacteria in normal household wastewater for proper functioning of the system.

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