Roebic septic tank treatment for sale at a building supply store (C) InspectApedia.comSeptic Tank & Drainfield Treatment FAQs
Questions & answers about the effectiveness, need, & safety of septic tank & drainfield treatments, chemicals restorers

  • SEPTIC TREATMENT FAQs - CONTENTS: questions & answers about the need for, safety of, and legality of septic tank treatments, chemicals, and drainfield or soakbed restorers and additives. Generally such Septic System Treatments are NOT recommended and may be illegal;
  • POST a QUESTION or READ FAQs about the need for and use of septic system treatments, chemicals, additives, restorers

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Septic tank maintenance FAQs:

This article reports questions and answers about the need for and effectiveness of septic tank treatments and additives to "keep a healthy septic tank" or to "restore a failed drainfield".

This article series discusses the need, choices, and use of septic chemicals or bacterial or other septic tank additives, septic system restorers, and septic tank treatments for septic systems. We cite expert sources all of whom advise against the use of septic treatments, additives, restorers and the like.

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Septic tank treatments, additives, enzymes, restorers: questions & answers

Septic treatment chemicals (C) Daniel Friedman

Question: blocked drain between septic tank and drainfield

What can I do if the drain pipe to the gravel from the septic tank is blocked? - Karwan 7/20/11


Clearing a blocked septic drain pipe between the septic tank and the drainfield?

First we need a diagnosis that requires either some digging or a plumber who has a remote camera that can inspect the interior of clogged piping.

If the pipe is clogged because the pipe has broken or collapsed the pipe needs to be excavated and repaired.

If the pipe is clogged by roots, you can have the pipe cleaned by a mechanical "roto-rooter" type drain service but root growth will return unless you find and remove the offending plants.

If the pipe is clogged by sewage that tells me that the baffle in your septic tank has fallen off or deteriorated and you're sending solid waste into the drainfield - which ruins the field; at a very minimum you'd pump the septic tank and install a replacement Tee or baffle.

Search our website for any of those terms to see detailed articles with more explanation.

Question: septic tank leaked into the ground and is near a creek, what can I put into the soil?

My tank has leaked into the ground which is about 25 ft. from a creek. Is there anything I can put in the soil to clean up it up, that won't harm the creek? - Mike S. 9/26/11


Mike I'd do the following:

- make sure that the leaky septic tank has been repaired - that stops an ongoing problem that is more harmful to the environment than a single event leak
- direct surface runoff away from the septic tank leak area as much as you can,
- give the natural soil bacteria time to process the pathogens that leaked from the septic tank

Question: Aerobic system producing excessive sludge

Hi - Great article. I am having an issue with my aerobic system producing excessive sludge that is floating on top of my tank. House and system are 5 years old and I have already pumped the tank 8 times. Sludge reappears within 2 months of pumping. We have adjusted the height of the pipe in the tank and have rebuilt the aeration unit. All contractors are stumped. What could cause so much sludge (bulked bacteria) to form?


Mike I'm not sure what's going on either. I'm reluctant to suspect water chemistry and tend to suspect a design issue, presuming the usage and type of wastewater entering the system are normal. If it were a nursing home I'd suspect a problem with antibiotics.

Meanwhile, you might want to get a detailed description of the design specs for your system and then check what's actually installed against the manufacturer's recommendations. Chances are if the aerobic equipment is working properly and the septic tank usage is within its design specs, you wouldn't have excessive sludge. So it could be a pump problem, aerator problem, or other installation issue. It would help to have a guess at whether or not this is a new problem.

Keep me posted.

Really?: OK so there are some exceptions to the "no septic tank additives or treatments are needed" rule.

While septic tank chemicals, treatments, additives are both unnecessary and often prohibited for conventional septic tank & soakbed or leachfield systems, there are exceptions: occasional treatments with a dry-pack (or wet pack) of beneficial bacteria may be recommended by the manufacturer / designer of BAT or biologically accelerated treatment septic systems and for some aerobic septic treatment systems that are left un-used for six months or longer.

That's because some septic designs continue to treat and remove bacteria during periods of dis-use. But in an ordinary septic system the tank and its wastewater are not normally sanitized.

See BAT MEDIA SEPTIC PLANTS for an example of cases in which a septic design or manufacturer recommends the replenishment of septic tank bacteria formulated for use with aerobic or BAT (Biologically Accelerated Treatment) septic systems.

Question: can I use Arm and Hammer Laundry Perfume and dye free powder in a graywater lagoon?

I am trying to figure out if I can use Arm and Hammer Laundry perfume and dye free powder in a gray water lagoon. The gray water system stays in a pond area and uses natural filters. This water only filters is never used again in watering or other uses. - Anonymous 10/20/11


If you are asking about using A&H laundry products at normal household usage levels it should not harm the lagoon system.

If you are asking about using such products to somehow "treat" the lagoon system, that would not be appropriate. Don't do it. If the lagoon smells, something is wrong with its design, use, or operation and maintenance that needs correction. A cover up of deodorant would be a mistake and risks contaminating the environment.

Reader Question: adding a bioculture to a septic tank treatment?

Is there any criteria for addition of bioculture in septic tank treatment? - S.D. 11/21/2013

Reply: no.

Yes, as discussed in the article above, there is absolutely no need to add bioculture to a septic tank. The best of these products do no harm, even though they are unnecessary and do not help. Worse, some such treatments are harmful, and in many jurisdictions, septic tank additives are illegal.

Normally, even after pumpout and cleaning, there is adequate bacteria starter in a septic tank for it to work properly.

Even in a brand new septic tank, the first flush of wastewater into the tank and drainfield initiates the procedure.

No septic tank additives are necessary. No expert, unbiased source, says otherwise.

At InspectApedia in our septic system articles in the References section you will see citations of authoritative sources. To be generous to the bioculture sales companies, there are indeed cases in which the septic tank bacterial colony may be harmed.

An example is a septic tank serving a nursing home. In some such cases, the high volume of antibiotics entering the septic tank can kill off the necessary tank bacteria.

However, in such cases, adding an after-market product such as a bioculture is futile. It too will be promptly killed off. A different wastewater processing design may be needed in such special cases.

A second example is the flushing of quantities of chemicals into the septic tank; (normal usages of laundry detergents and bleach are not an issue). In such cases the wastewater effluent becomes an environmental contaminant and tank bacteria may be harmed or killed off. In this case as well, adding a bioculture is not a functional solution; rather, ceasing the improper disposal of chemicals into the septic tank is required. ‚Äč

Finally, there MAY be some packaged wastewater treatment system designs that require certain chemicals or preparations in regular maintenance, but this does not describe standard septic tank and drainfield installations nor aerobic septic systems.

Question: add caustic soda to the drywell?

(Apr 10, 2014) Anonymous said:

After the septic tank and dry well were pumped and inspected the septic pumping company said to add 50 lbs. of caustic soda to the dry well. While I do think they are incorrect, I cannot find 50 lb. bags to buy other than online and see there is a safety issue and possible other shipping problems/expenses. Is this necessary and if so, is there an equivalent alternative product that can be easily obtained without shipping costs?



In the "More Reading" article links above, click on


I understand that pouring a toxic contaminating chemical down into a drywell might somewhat break down sludge therein but geez: why would you contaminate the aquifer, possibly your own well, kill all bacteria within range (which of course ultimately means contaminate the environment further with sewage pathogens) and quite possibly violate the law.

Additives are not necessary, don't help, and are illegal in many jurisdictions.

Let me know what your local health department, water department, or building department say about this suggestion.

I wouldn't do it.

Question: roots in the septic system

(May 18, 2014) Mimi said:

Every time I have my tank pumped the septic guys want to put a new system in Now the reason seems to be roots at the outlet and d box

Their answer was to replace the whole system. 3 different septic companies with 3 different opinions

They make these claims with out camera inspections I say become and educated consumer with articles like this If your tank is not cracked not leaking there is no need to replace Cleaning and maintenance are the key Dont be sucked into expensive repairs



If a septic piping system has been invaded by roots, certainly that problem needs to be repaired. But if the septic tank itself is in good condition I don't understand the justification for replacing the tank as part of piping repair.

I agree with you.

However the root problem needs to be addressed. Simply using a power auger can remove roots from an otherwise "intact" sewer line. However one must consider how the roots got in the pipes in the first place. The roots have to find an opening.

If that opening is a broken or open joint the root blockage will recur, possibly sooner than you think. Using a root killer is not an effective long term solution and itself may harm the environment. In that case the solution is to excavate and replace the open or damaged sewer line.

If root invasion is happening in the drainfield, where multiple lengths of perforated pipe are used, there are trees or other plants closer to the drainfield than they should be. In that case, when the drainfield is rebuilt, the trees or invasive plants also need to be removed.

Question: required to use a septic treatment every month?

(July 5, 2014) Troy said:

We recently bought a 30 year old house that the previous owner had been using Septic Helper 2000 once a month.

I have continued to use it until the on hand supply ran out. I have heard that if you start using one of these biological aids that you needed to continue to use it in order to maintain the septic health. Is this true?


Troy, as we hope you'll read in the article above,



(July 7, 2014) Re-posting without prohibited link

Pumping Septic Tank said:

Thanks for describing these points about the continuous septic cleaning. The point by point representation will always helps to identify the important for us. Keep sharing the information like this in the upcoming pages.


Thanks for the comment; while our security system doesn't allow posting of links by readers in the comments box, we welcome content critique, suggestions, corrections from readers (use our CONTACT link to send email) and we're happy to cite and give contact information for content contributors. Question:

Question: iron removal treatment system impact on septic system

(Aug 27, 2014) betty said:

question: can the regen cycle of iron filter skew septic inspection results: my septic was pumped only 2 yrs ago, with only 2 people in home, 1000 gal tank, built in 2005...maybe 4 hours after iron filter cycled, septic was inspected- report of septic says "low scum and high sludge layer, needs pumping"--I am wondering if the sludge was disturbed and hadn't had enough time to settle?


A single regeneration cycle of water treatment equipment would not give a dishonest impression of the septic absorption beds. If a failure showed up under that condition then the test discovered a current or imminent failure.

But if water treatment equipment were stuck in re-gen mode, indeed it could flood the septic drainfield.

A septic report saying low scum and high sludge, presuming measurements were actually made, would be to be trusted. The sludge layer does not include suspended solids.

Question: treatment for roots entering the septic tank?

12/12/2014 Anonymous said:

What about roots in the tank?



Roots invade leaking drain pipes, but are not likely to be in the septic tank itself except at its piping entry / exit - conditions to be found and repaired at tank cleaning.

Question: Tried Roebic K57 Septic System Treatment Additive in D-box & Toilets - did not help

(Mar 23, 2015) Bruce said:

I have a 45 year old clogged drain field. I tried using Roebic K57 additive in both the distribution box and the toilets as recommended by the manufacturer and had no positive results. The 1000 gallon septic tank has been pumped twice in the last 8 weeks after the shower drain backed up and the toilets were bubbling.

The local septic company who pumped the tank said it's in good condition but the field is plugged.

They suggested jetting the drain field out and injecting the field with high pressure at several points to break up the bonding in the gravel bed. Cost would be $800. If that didn't work they said the drain field would need to be replaced. Cost $3100. I have heard that sodium percarbonate works but I need some input from you on your experience with it.

The recession killed us so money is tight and I need to know if there is a less expensive way to get the drain field operational again.

I'm in South Florida and the soil is sand. I am not the original owner of the house so I must presume that nothing has been done up to this point.


Thanks for the remarks and question, Bruce.

Indeed there is no septic tank additive for which I've been able to find scholarly research that supports the ability of a treatment chemical to repair a clogged, failed septic drainfield.

Other processes that attempt to aerate or pump styrofoam into the soil sound attractive and might give some relief but comments from our readers have not supported claims that even those approaches provide a long-term durable repair.

I suppose that the effectiveness of soil break-up restoration techniques may perform better in some soil types than others.

I would not use any chemical treatment not only for reasons we've already discussed but because harsh chemicals risk both environmental contamination and the kill-off of soil bactgeria that are needed for effective drainfield function.

Before digging up the whole field to replace it, it'd be nice if we could rule out a blockage due to a broken or collapsed pipe between tank and fields; Just where you are seeing effluent break-out in the drainfield area might suggest an answer.

It might be instructive to dig a clean cross-section of one of your drainfield trenches to get actual visual data of what's going on (send me some photos if you do this) and since most likely you need a new field system anyway, not much time or money would be wasted by taking a nice visual slice of the system first.

Question: safe for my septic tank and pipes to use Plumb Clean ?

(Apr 9, 2015) Wendy said:
Is it safe for my septic tank and pipes to use Plumb Clean to keep the sinks clear. Plumb Clean contains plumbenzymes and mycrobes.

Sorry, I made a mistake, the Plumb Clean contains Plurazyme enzyme blend and microbes. Again, would this be harmful to the septic tank if I use this in sinks on a reasonably regular basis - recommended 5 days in a row, then stop. I couldn't find an answer to this in the FAQ
Thank you


Anon / Wendy:

Plumb Clean is an enzyme drain cleaner; it should not harm the septic tank. However in normal household it is not necessary to regularly add a drain cleaner / clearer to the plumbing system. The system should drain properly without additives. If you find that you need to do so then there is a problem with your system that needs to be found and repaired.

Question: rotten egg smell when we turn the pump on

(May 27, 2015) Shirley said:

Please help... We are new to septic tanks and soakaways and we was told to put pump on every other day but every time we put pump on we get a smell of rotten eggs... What are we doing wrong...? Do we need it checked...?


Shirley I don't know what sort of pumping system you have, but if you are describing a sewage ejector pump to empty out a reservoir in a building or a septic effluent pump that is intended to move effluent up to a soakaway bed, both of those pumps are normally operated automatically by a float that senses the level of sewage in the holding tank. So it sounds as if your installation is defective or incomplete.

There should be no indoor odors. If there is one I'd be looking for a check valve problem or a venting problem or a leak.


Question: big root in the septic tank - how long to decompose?

(Aug 5, 2015) Dave said:
I had my septic tank pumped 1 year ago. It had a very large root in the tank and was floating at the top of the tank. When the tank was pumped it broke and fell to the bottom of the tank. We cleared away the roots on the outside of the tank and sealed it so they couldn't enter the tank again. Will that large dead root decompose and if so how long will it take? Our lines are clear of any roots. Also the level of the water was about 5" below the bottom of the inlet pipe.



While like you I'd have rather had the root removed from the septic tank, as long as it is on the bottom and not blocking an inlet or outlet opening of the tank, it won't hurt a thing. The volume occupied by the root is trivial even if it takes a decade or more to decompose

Watch out: if the root grew into the septic tank then the tank is cracked or otherwise damaged, leaking, and needs repair or replacement.

Question: need a chemical to dissolve floating scum layer in septic tank

(Aug 18, 2015) andrew said:
I have septic tank but i has formed hard sludge coating on top about 10 inches so i need a chemical that can dissolve
that sludge but should not affect or kill the bacterial.


Andrew there is no such chemical or treatment that I can describe nor recommend, and in fact such additives or treatments are generally unnecessary, sometimes harmful, and are prohibited in many jurisdictions.

The floating scum layer is normally broken up and removed during septic tank pumping/cleaning. It sounds as if that is what you need.

Question: how to find field pipe coming out of tank

(Sept 4, 2015) mike said:
how to find field pipe coming out of tank


Mike the pipe exiting the septic tank will be at the opposite end of the inlet end. If you can find the tank you've found the pipe. For more complete help in finding septic components see


Question: greywater line keeps clogging

(Oct 28, 2015) Christine said:
I just unclogged our grey water line 5 months ago and its plugged again. What can i do to prevent this every 5 months? It just washing machine and water from washing dishes that goes in the grey water line.


SEPTIC FILTERS can address this problem.

Question: septic company says medications we take can kill off septic tank bacteria

2015/11/06 Larry said:
Our septic has had to be pumped every 6 months recently, We don't put anything down we shouldn't. The company that pumped said that taking medication could kill off the good bacteria in the tank. Is that true? My wife and I are both taking medication. Could this cause a problem?


Having to pump a septic tank every 6 months does not fix an underlying problem of an under-sized or poorly designed system or more likely a failed drainfield; it doesn't make sense to me unless you're using your system with a failed drainfield and treating it as a semi-holding tank; a septic tank at a typical home is re-filled in a few days after pumping; faster if groundwater is leaking into the tank; so it's not right that the septic tank should be kept below its normally-full level.

See a detailed answer to your question and supporting research found

Bottom line on septic treatments

Septic tank treatments and additives are not necessary for conventional septic tanks & absorption fields, some can contaminate the environment, others can destroy a septic drainfield or soakbed, none will repair a failed drainfield, and such products are at best usless and at worst harmful. This is the view of all of the septic system authorities we've found and are the views of most engineers and sanitation professionals. Those expert sources are cited here.

Exceptions to the generally-true "use no septic treatments" can arise however for some advanced-design septic systems such as some aerobic or biologically-accelerated treatment (BAT) septic system designs.

Types of septic system treatments and restorers, their use and effects are addressed here. Our page top photograph shows a collection of septic system additives, chemicals, cleaners, root killers, etc. for sale at a building supply store.

InspectAPedia is an independent publisher of building, environmental, and forensic inspection, diagnosis, and repair information provided free to the public - we have no business nor financial connection with any manufacturer or service provider discussed at our website.

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InspectAPedia is an independent publisher of building, environmental, and forensic inspection, diagnosis, and repair information provided free to the public - we have no business nor financial connection with any manufacturer or service provider discussed at our website.


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