PHOTO of the septic tank washdown after pumping. Cleaning the Septic Tank, How & Why to Wash Septic Tank Interior

  • WASH SEPTIC TANK SIDES/BOTTOM - CONTENTS: Washing the septic tank after pumping, how and why we do it . Washing Down Septic Tank Sides/Bottom.Do we need to wash down the septic tank interior ? Is it ok to see bits of stone or masonry on the bottom of the septic tank?Spotting septic tank cracks in sides or bottom. Can we enter the septic tank to repair cracks or leaks? Fatal hazards at the septic tank.
  • POST a QUESTION or READ FAQs about how & why to wash down a septic tank interior after pumping.

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Septic tank cleaning procedures:

How and why the septic tank interior is washed down after tank pumpout. Cleaning the septic tank during and at the end of the septic tank pump-out procedure can expose damage to the septic tank sides and bottom that cannot otherwise be found.

This septic tank pumpout article series provides a step by step, photo-illustrated guide to opening, pumping, and inspecting septic tanks, how a conventional septic tank is located, opened, pumped out, cleaned, and inspected. This guideline is intended for septic pumping tank truck operators and as general information for homeowners or septic service companies concerned with septic system care.

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Recomendations for Washing Down Septic Tank Sides/Bottom After Pumpout is Completed

PHOTO of the septic tank washdown after pumping.

After the septic tank is nearly empty the operator might connect a garden hose to wash-down the tank baffles, septic tank sides, and tank bottom. The pump will continue to run to remove the excess water that is entering the tank.

This step is not mandatory, and some septic pumping contractors leave it out. But if it is performed we have an opportunity to better inspect the septic tank sides and bottom for cracks, breaks, or spalling. In sum, washing the septic tank permits a more careful inspection of the condition of the septic tank interior.

The additional water in the septic tank and any remaining bottom debris is washed out at this time.

The need for septic tank interior washing depends on the tank type, age, and conditions which may require extra water for final sludge removal or wash-down to permit inspection of suspected problems such as a rusted-out tank bottom or missing tank plug. Certainly if the effluent levels in the tank were abnormally low at the start of pumping, this wash-down and detailed inspection is a good idea.

Incidental bits of masonry debris in the bottom of the septic tank such as chips from a concrete cover, stones, or old terra cotta waste line which happen to remain on the tank bottom may remain in place and are harmless.

If septic tank damage is found such as cracking, it may be possible to repair the septic tank by cleaning the surfaces and applying an appropriate masonry patching compound. But no one should enter the septic tank without proper equipment or preparation as there is a real danger of death by asphyxiation by the methane gas remaining in the tank.

PHOTO of the septic tank washdown.

Reader Question: septic tank pumpers who churn and return sewage to the tank

(May 16, 2012) Bob said:
The septic pumping contractors convinced our municipalities that after a septic tank has been emptied it should be immediately refilled (to its original level) with effluent from the pumper truck - claiming that a) gravity in the pumper truck's tank separates the solids from the liquids (during the 5 to 10 minutes the effluent is in the truck) so that mostly only liquid is returned to the septic tank; and b) that this return of effluent improves septic performance. I can see the financial advantage for the contractors (fewer trips to the water treatment facility; lower disposal costs; charge homeowners extra $$$ for 'complete' emptying) but I cannot find any independent evidence from a reputable source that supports these claims. Does anyone know of any sources that actually support these claims? Thanks!


Bob, you also posted your question at the end of the article titled INSPECT the SEPTIC TANK AFTER PUMPING. There we have provided a detailed reply to the improper and destructive septic tank effluent churn-and-return procedure you describe below.

You might want to warn your municipalities as well as the pumpers that once homeowners discover that the approach you describe is going to cause very costly damage to the septic systems (by pushing solids into the drainfields) as well as environmental damage the pumpers and municipalities are inviting class action litigation by the aggrieved homeowners.

Below at in the form of individual detailed articles are the Steps in Septic Tank Cleaning Procedure in the order that they should be performed:

Septic Pumping Procedure & Pumper Truck Operation Articles


Continue reading at INSPECT the SEPTIC TANK AFTER PUMPING or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see CLEANING SEPTIC TANKS - home: basic information for homeowners

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