New research finds that 20% of septic tanks were not desludged in the past five years

October 17, 2024

Energy and Environment
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New research, published by the ESRI, and produced in partnership with the Department of Housing, Local Government and Heritage finds that one in five septic tanks were not desludged in the past five years. Additionally, most households sourcing their drinking water from a private well do not regularly send their water for laboratory testing, as recommended by the Environmental Protection Agency. 

The study is based on a survey of over 1,800 registered owners of a domestic wastewater treatment system (DWWTS), i.e., septic tanks, which collected owners’ views and experiences related to drinking water, septic tanks, public health and the environment.

Key findings

Drinking water testing

  • Just one in five households with a private well supply has had its water tested in the past three years. The most common reason for not having water tested is that there is no (perceived) problem.
  • Households with members who have health vulnerabilities are not more likely to test their drinking water than those without such health vulnerabilities.  

Septic tank desludging

  • For households that have not emptied their septic tank, the primary reason for not doing so is a belief that it isn’t necessary. The cost was not indicated as a significant contributory reason.
  • Among households that desludge their septic tank, the majority are aware of the operational benefit of regular desludging, while a substantial minority are also aware of the environmental protection benefits.
  • Households with ultraviolet light treatment on their drinking water supplies are half as likely to desludge their septic tank compared to those without ultraviolet light treatment.

Remediation of septic tank malfunctions

  • Most households indicated that they have never experienced specified symptoms of a malfunctioning septic tank.
  • Approximately 10% of surveyed households had observed symptoms of poorly functioning septic tanks within the past five years. Most households attempt to resolve these problems. Of the 2-in-10 that have not attempted to remediate a malfunctioning septic tank the most prevalent reasons for not doing so is that the problem isn’t perceived as severe, or that it’s too much hassle to fix the problem

Policy recommendations

Drinking Water

  • Given the knowledge deficit on the importance of regular testing of drinking water from private supplies, new communications strategies should be developed to address this issue.
  • Making it easier for households to choose a suitable testing laboratory is paramount, for example, maintaining an approved list of certified testing laboratories.

Septic Tanks

  • A recurring communications strategy should be developed to alert households of the public health and environmental damage risks of not undertaking regular septic tank maintenance. The Protect Our Water register of DWWTS is an ideal resource for communicating with relevant households.
  • Ultimate responsibility for septic tank maintenance falls on households but there is a public good case to reduce the organisational burden on households associated with sourcing suitable contractors for desludging.
  • In addition to better communications strategies, and reducing administrative burden, greater enforcement activity is also critical. Inspections of domestic wastewater treatment systems (DWWTS), including septic tanks, should increase substantially.

Professor John Curtis, author of the study said:

“While most septic tanks are regularly maintained, where that is not the case, there are risks to public health via contaminated drinking water supplies, and also to the environment. Lack of awareness of the environmental and health risks is a key issue, but apathy is also prevalent. Therefore, policy action should include an educational element, as well as, greater enforcement actions.”