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PHOTO of a concrete septic tank baffle and inlet pipe in use. Septic Tank Baffle or Tee FAQs
Diagnostic questions & answers about septic tank tees or baffles

  • SEPTIC TANK BAFFLE / TEE FAQs - CONTENTS: diagnostic & repair questions abouit septic tank baffles and septic tank tees: lost, rusted, or damaged septic tank baffles. Causes of septic tank baffle damage. Effects of septic tank baffle damage on the septic drainfield life.
  • POST a QUESTION or READ FAQs about how to find, inspect, and troubleshoot the septic tank baffles or tees
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FAQs about septic tank baffles & tees:

These questions & answers can help diagnose problems traced to septic tank baffles or tees including lost or damaged tank tees, sewage overflowing the top of baffles, baffle or tee replacement, measurement, installation specifications.

This article series describes how to inspect the condition of septic tank baffles at the septic tank inlet baffle and septic tank outlet baffle ports.



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Septic Tank Baffle & Tee Frequently Asked Questions FAQs

Septic tank dual compartment - Alaska DEC[Click to enlarge any image]

In the sketch at left the inlet and outlet septic tank baffles or "tees" are shown in brown and light blue respectively. You can see that the inlet tank baffle or tee will direct incoming wastewater down into the tank (not zooming across a tank to rush to the outlet opening).

Question: ok to chip a hole in the concrete tank to connect piping?

(May 23, 2014) Sophia Liam said:

Does chipping away at the concrete of the tank to put in the piping cause the tank to be more at risk for cracking in the future? This article was super interesting, so I'm just looking for a bit more information. You've got a great blog going here.

Reply:

Sophia, septic tanks are normally cast with an opening for pipe connections. Chipping at the tank shouldn't increase the crack risk, but indeed any discontinuity in a concrete casting (e.g. windows in a foundation) can create a variation in stress that can be the locus of a future crack.

Question: elbow rather than tee at septic tank inlet

(June 7, 2014) Patrick said:
I've been reading this website off and on for two years as I've had ongoing struggles with my system. Recently I discovered my line was busted between my house and the tank. In digging it up and clearing it out, I also discovered that my inlet appears to be cast iron into a concrete tank. The inlet appears to be more of an elbow instead of a T.

Also, the inlet seems to have corroded and severely narrowed the opening into the tank, likely causing the backups that lead to the pipe failure. Is there a way to "bore out" the cast iron inlet that is corroded, or do I need to look at replacing my inlet (and likely outlet) pipes? Can an expert knock out the old cast iron inlet and replace it with a new plastic one without damaging the tank?

Reply:

Patrick,

I would excavate the tank inlet end, break out the corroded cast iron, and if there is no intact tank baffle inside the septic tank I'd cement a new plastic tank tee in place, sealing the tank opening around the tee with hydraulic cement or if the surfaces are clean and dry, a suitable flexible sealant.

IF the tank baffle is intact you can go straight into the tank in the baffle area with a new plastic line connection, just stop the projection in the tank flush with the tank wall.

Question: can I use an elbow instead of a tee

(June 16, 2014) brian said:
I currently have a single 500 gallon round concrete tank with just one lid. The top of the tank sits 5 feet below grade. As far as I know the baffles are good on either end. If they were to be damaged is there anything that could be done with just an elbow instead of a tee and still work? Could i use a tee and drill the top of the tank and run a pipe to the surface?

Reply:

Brian I'm unclear on why you want to use an elbow instead of a Tee - which would make inspection and cleaning rather difficult and might increase the clog risk.

If you are thinking of inserting a Tee as an outlet or inlet baffle and wanted to extend that to the surface I'd prefer to install a septic tank riser of larger diameter, making inspection and cleaning much easier, but yes one could just extend a tee to the ground surface. Be sure to seal against leaks into the septic tank.

In the FAQs section of our sister article SEPTIC TANK TEES you'll see more about why installing elbows instead of tank tees is not a good solution for septic tanks. You may need to click to show and read those faqs.

Question: ok to build a floor over the septic tank?

(June 26, 2014) Don said:

Is it safe to put a concrete floor over a septic tank?

Is it safe to put a concrete floor over a septic tank? The flooring is around 4 inches, the only outlet pipe would be the one heading to the municipal sewage system.

Will there be methane problems?

Reply:

Don

With proper support the concrete floor may be "safe" but it's a design that makes for some big trouble in a year or two when the septic tank needs to be pumped.

You need to keep adequate access to inspect, repair, clean the septic tank.

Question: cost to install a septic tank baffle tee

(July 14, 2014) Mike Brantley said:
I was charged$1,058.06 to install a rear and a front baffle tee on my septic tank. That seems very high to me for Parts that cost around $50.00. I would appreciate your thoughts and thanks for your time.

Reply:

Mike

It might have been gouging, or it might have been quite fair. The parts are often the least costly part of a job. Other costs such as excavation and restoration work or pumpout if that was part of the job would of course increased the job cost.

Question: ok to move a septic tank inlet

(July 17, 2014) Keith said:
I have a septic from the 1980s and have built a new house going from a mobile home. With a square septic Is there only one inlet and outlet front and back or is there also one on the side it can be switched too. Currently inlet is north and outlet is south. Can the inlet be moved to the west.?

Reply:

Keith,

Most likley, yes, but you'll need to look into the septic tank to be sure that there is (or you'll need to add) an inlet baffle at the new inlet connection

Also, watch out: going from a mobile home to a new house, the size and capacity of the septic tank and drainfield may be inadequate.

Question: hubbie says don't need septic tank tees

(July 27, 2014) Amy said:
The outlet pipe to our leach line is straight out and does not contain an elbow to kkeep it below the scum level. Our leach lines continually build up with gunk. I told my husband we need an downward facing elbowed outlet pipe . He said no because then he can't flush out the leach lines easily. We don't have a d- box. Who's right?

Reply:

Amy you are completely correct.

Omission of the Tee or baffle at the septic tank outlet very seriously shortens the drainfield life by pushing solids out into the field piping.

Install an outlet tee or baffle.

The lines to the drainfield should not need "flushing" - if your husband thinks they do, it's because your septic system has been pushing solids into the piping.

If hubby still wants an opening to mess with the drainfield piping he should install a D-box outside of the septic tank between the solid line feeding the drainfield and the perforated drainfield piping network.

The details of your note make me worry about the correctness of the design and installation of your system.

Question: septic tank is full and overflowing - are the leach lines OK?

(July 29, 2014) Keith C said:
Septic tank is full and distribution has also been unearthed and is also full and overflowing. I purchased a sump pump and pumped all the grey water off and down to the bottom of the distribution box. I watched the flow from septic tank going into distribution box. I did'nt see any flow going thru the field lines.

My question is are my field lines full or are they possibly collasped? The system is at least 40+ years old.

Reply:

Keith if no effluent flows into the leach lines most likely the drainfield is saturated, flooded, or lines blocked. Try a test excavation at the end of one or more drainfield lines.

Question: pumping the septic tank every 6-9 months, exploring piping

(Sept 20, 2014) 9yr old house - continuous clogging of inlet piping said:
9yr old house. For the past several years, we have not been putting toilet paper in the toilet, because we were having to get our system pumped every 6-9 months.

Right now there is no problem from the primary tank on. With increasing frequency, whenever we have a visitor, the system clogs.

Responding, I use the snake from the primary tank toward the house and generally dislodge some visible amount of paper or otherwise release the clog and the system flows freely into the primary tank.

These days it takes someone visiting for just one night for the inlet to not work properly.
At this point I am considering digging down to my inlet pipes to find if some part has collapsed or is compromised and has become infiltrated by weeds. I've never seen weeds come out of the inlet.
Any suggestions would be appreciated.

Reply:

Inspect at the tank for condition of the baffles, for back flow into the tank from the drainfield, and then as needed check piping, perhaps by camera.

Question: OK to use a 90 degree elbow instead of a septic tank tee?

(Sept 25, 2014) Gene said:
Can you use a 90 or must one use a T? Is it safe to assume it needs to be 16-18 inches long?

Reply:

Gene

I've seen 90's but a tee gives you the ability to see and clear clogs while the 90, pointing down, does not.

The tee also will allow sewage to overflow at the tee top and enter the septic tank if the tee outlet becomes clogged. A clogged 90 degree elbow outlet will give you a sewage backup in the building.

I'd stick with a Tee.

Question: septic pumper brok off the tank tee - do I need it fixed?

(Nov 23, 2014) Brandy Schultheis said:
I just had my septic tank pumped for the first time. It was installed 3 years ago. The company we had do the pumping broke a tee pipe off that was in the septic tank and also broke the seal out of the tank where the inlet pipe is. Are these both important to the proper functioning of the septic tank?

He broke them off and was going to leave the tee pipe just floating in the septic tank itself but we had him get that back out of it. He then charged us for all the things he broke. I just need to know how important these are to the tank.

Reply:

Brandy

Absolutely - the broken tee should be replaced as soon as possible - lest you push solids into and destroy the drainfield.

And a broken pipe seal at a septic tank inlet or outlet risks admitting ground water into the tank, flooding it, or risks permitting septic effluent to leak out ant an improper location.

Question: can an air leak in piping cause a septic tank backup?

(Dec 6, 2014) Mike bevens said:
Can a air leak on the main4 inch valve going out to the septic tank cause a backup inside the drain pipe

Reply:

Generally if there is a leak in a septic line you'll more likely see effluent leaking out or sewer gas leaking out.

Question: I paved over the leachfield - soakbed - is that OK?

9 Jan 2015 Anonymous said:
I had my 900 gallons septic tank pumped two years ago. Prior to that I pumped it three years earlier and after three years it clogged up. I uncovered it closest to the house today to see how it is doing and it appears to pretty full. Is that normal? The scum is about 4" below the inlet "T"

. When I flushed the toilet and watch the water entering the septic tank it was coming out of the top of the "T" instead of the bottom. Is that normal?

There are only two of us living in the house full time a only a few times a years do we have company and heavy use on the tank. I did pave over my leach field and plant plants over another section of it. Did I compromise the leach field by doing so? I have friends two doors away that pump their tank about every fifteen years.

Your advice will be greatly appreciated. Thanks

Reply: paving over the drainfield is a serious error

Anon

Keep in mind that while pumping the septic tank on schedule can help preserve the life of the drainfield, once the fields are in failure, pumping doesn't fix anything

Waste coming out of the top of a tee suggests that either the tee bottom was blocked or the drainfield is saturated. Try clearing the tee bottom and checking the thickness of the floating scum and settled sludge layers.

You don't ruin a leach field with a small single event of sending it solids but yes, in general that's indeed a way to speed leachfield demise.

Tank pumping frequency is given and explained

at

SEPTIC TANK PUMPING SCHEDULE

Watch out: paving over a septic drainfield is likely to destroy it, first by damage during the driving of paving vehicles over the field and second because the pavement prevents part of the field's functioning that requires transpiration or evaporation of a portion of the septic effluent and third because the cutoff of oxygen from the soil will halt operation of and kill off the required septic digesting bacteria needed for proper effluent treatment.

Question: put in a new septic leach field and we are still smelling septic

(Jan 13, 2015) Anonymous said:
we put in a new septic leach field and we are still smelling septic

Reply:

Anon I can't know if the septic odor is due to a bad baffle, but more likely there was a septic backup or spill that has not been cleaned-up, or sewage-contaminated soil has been left exposed.

Question: not getting any flow into my D-box

(Feb 3, 2015) Bill Conner said:
I am not getting any flow into my D-box and I had to remove the toilet that was in my garage because it was broken,

Now all of the effluent water is coming out of the opening in the garage. The tank was pumped out last month but it did not fix the problem at the D-box, I ran a 40' snake down both of the leach lines and made sure that they were clear, I then tried to run the snake from the d-box to the tank and It got hung up just as it began to enter the tank.

Could it be contacting a broken baffle? and would this stop the liquid from reaching the D-box?.I was thinking that there was a clog of solid waste at the baffle area that the pumping did not remove, the tank was very full of heavy solid waste when pumped and perhaps the operator thought this was the end of the tank.

Anyway do you think using a commercial treatment such as NT MAX would help break down the clog or what do you recommend. Thank You for any help. Bill

Reply:

Ugh. Sorry to hear about that mess.

It really sounds like a blocked line that's causing sewage to back up through the easiest available route.

I would scope the lines before trying chemicals. If you're lucky there's a repairable break or clog.

I would NOT want to push solids further out into the leach field - which will only kill it off more quickly.

Question: getting scum and partial solids clogging percolation pipes

(Mar 22, 2015) Dan said:
Hi,
I installed a new exit pipe from an old septic tank to a percolation area with the proper perforated pipe network with vertical open vents. I have tee baffles on both inlet and outlet pipes. The liquid level is correct with a fine scum on top but I appear to be getting slight scum and partial solids clogging percolation pipes, tank was cleaned last year. How much of a level distance should there be between inlet and outlet baffles if any?

Reply:

Dan

In a normally functioning septic tank the top of the liquid in the tank should be just at / below the bottom of the outlet pipe at the tank exit.

The bottom of the inlet opening is normally an inch or few higher.

But more to the point of your complaint, if the septic tank is too small or is being agitated by treatments that can push solids out into the drainfield. See EFFLUENT RETENTION TIME for an explanation.

Try installing a septic filter system at the outlet baffle/tee. That'll mean more maintenance but it'll keep crud out of the drainfield.

Question: why does a deteriorating baffle have to be replaced

(May 21, 2015) vicki said:
why does a deteriorating baffle have to be replaced if it still works

Reply:

Vicki

I'm not sure I understand the question, nor that I disagree with "if it still works" provided that "works" is accurate.

"Works" in my view means that a component is sufficiently reliable that we can forget about it without having to face undue risk of a catastrophe - such as a clogged sewer line and backup into the building.

So a concrete septic tank baffle with a couple of chips out of it is fine. But a septic tank baffle that is cracked, falling off, or that shows signs of having been over-flowed means that diagnosis and repair are needed, and a baffle that has been lost needs to be replaced promptly.

Question: do septic tank baffles need a vent hole?

(May 28, 2015) Bill said:
do the baffles need to be vented and a 1" hole +/- be provided?

Reply:

Bill:

Because the normal waste level in a septic tank is always below the upper edge of any type of septic tank tee or baffle, they do not need additional venting.

If you see sewage flooding over the baffle top then the tank is flooded, its outlet is blocked, or the drainfield or soakbed has failed.

Comment:

Derrick Sly said:
I'm glad to find something about baffles. Honestly, there isn't enough information on their inspection and maintenance on the internet. It's a big deal, because the baffles make up a very important part of your system.

Question: can an air leak in piping cause a septic tank backup?

(Dec 6, 2014) Mike bevens said:
Can a air leak on the main4 inch valve going out to the septic tank cause a backup inside the drain pipe

Reply:

Generally if there is a leak in a septic line you'll more likely see effluent leaking out or sewer gas leaking out.

Question: I paved over the leachfield - soakbed - is that OK?

8 Jan 2015 Anonymous said:
I had my 900 gallons septic tank pumped two years ago. Prior to that I pumped it three years earlier and after three years it clogged up. I uncovered it closest to the house today to see how it is doing and it appears to pretty full. Is that normal? The scum is about 4" below the inlet "T"

When I flushed the toilet and watch the water entering the septic tank it was coming out of the top of the "T" instead of the bottom. Is that normal?

There are only two of us living in the house full time a only a few times a years do we have company and heavy use on the tank.

I did pave over my leach field and plant plants over another section of it. Did I compromise the leach field by doing so? I have friends two doors away that pump their tank about every fifteen years.

Your advice will be greatly appreciated. Thanks

Reply: paving over the drainfield is a serious error

Anon

Keep in mind that while pumping the septic tank on schedule can help preserve the life of the drainfield, once the fields are in failure, pumping doesn't fix anything

Waste coming out of the top of a tee suggests that either the tee bottom was blocked or the drainfield is saturated. Try clearing the tee bottom and checking the thickness of the floating scum and settled sludge layers.

You don't ruin a leach field with a small single event of sending it solids but yes, in general that's indeed a way to speed leachfield demise.

Tank pumping frequency is given and explained

at

SEPTIC TANK PUMPING SCHEDULE

Watch out: paving over a septic drainfield is likely to destroy it, first by damage during the driving of paving vehicles over the field and second because the pavement prevents part of the field's functioning that requires transpiration or evaporation of a portion of the septic effluent and third because the cutoff of oxygen from the soil will halt operation of and kill off the required septic digesting bacteria needed for proper effluent treatment.

Question:

(Apr 8, 2015) Ken NJ said:
I just had my 1000 gallon septic, 4 years old, pumped. All went well. The service man said there was a flap at the base of the inlet but no flap at the base of outlet.

He also said he could put a removeable filter on the view port which can be cleaned or replaced. All for $300.00. Also said NJ requires now on new installs. Is this sound feasible?

Reply:

Sounds like a great deal to me.

Be SURE however to find out about the maintenance requirements for the filter, and to follow them.

Use our CONTACT link to find an email and send along photos of the filter and equipment being installed and we can comment further.

Question: do I need to replace a damaged septic tank inlet baffle?

(Apr 29, 2015) Anonymous said:
Septic being pumped. Guy said inlet baffle is damaged. Want to put new one on. 150 cash. Said outlet is fine. Do I need inlet??

Reply:

Anon:

Yes you need a working inlet and outlet baffle on a septic tank. To leave it off is to ask for a clogged waste line, sewage backup, and a mess.

Question: height of septic tank inlet and outlet pipes

(May 13, 2015) mike said:
if a septic has a pump uphill system, does the height of the inlet and outlet pipes matter?

Reply:

Great question, Mike.

Yes height matters. All pumps of all type have a rated lift capacity. It's not an absolute number.

Rather, the higher the lift, the lower the gpm flow rate capacity the pump can deliver. But ultimately if the lift height is too much the pump won't work or will burn out or have a short life.

And at a properly-installed septic tank the inlet end will be a few inches higher than the outlet end pipe connection. Otherwise sewage wants to back up in and clog the inlet piping.

Septic Tank Care Articles

...


Continue reading at SEPTIC TANK BAFFLES how to detect a lost or damaged septic tank baffle or a damaged tank tee; when & how to add a septic tank tee or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES.

Or see SEPTIC TANK TEES - replacements for lost or damaged septic tank baffles

Or see FILTERS SEPTIC & GREYWATER to add a septic filter or graywater filter to extend the life of septic tank, soakpit, soakaway bed, drainfield, leachfield, or drywell or cesspool.

Or see SEWAGE LEVELS in SEPTIC TANKS for details on normal and abnormal levels and what they mean.

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SEPTIC TANK BAFFLE / TEE FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

INDEX to RELATED ARTICLES: ARTICLE INDEX to SEPTIC TANKS

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