Septic System questions

Discussion in 'Drain Cleaning' started by Smith333, Nov 29, 2008.

  1. Smith333

    Smith333 Member

    Messages:
    107
    Our house is 35 years old and still has its original septic system. The soil in the area of the leach bed is gravel and drainage has never been a problem. However, the system has backed up twice in the past 10 years. Each time we had the tank pumped, and the line from the tank to the distribution box snaked, which cleared up the problem each time. The snake he used each time was a manual snake that he simply pushed back and forth until the effluent started flowing again.

    After the first backup, we started having the tank pumped every 2 years instead of 4-5 years. The last backup was 3 years ago, at which time we decided to have the tank pumped every 18 months. There have been no problems since.

    The most recent pumping was a few weeks ago, and I had the chance to talk with the licensed plumber (restricted sewer) who did the pumping about the issues we've had. He explained that the concrete tank is still in good condition and the leech bed *seems* good based on (1) visually examining the vent pipe at the end of the bed, (2) being able to detect suction from the vent pipe when he put his pumping tube into the opening leading to the pipe out of the tank, and (3) the fact we have never had any sewer smell from the vent pipe. He suggested the following:

    1. Replace the 4" cast iron pipe between the tank and the distribution box with 4" PVC. This is the pipe that has clogged twice. He's not sure how long it is, but guesses 10 to 20 feet.

    2. Replace the U-shaped baffle (which is still in good condition) with a PVC Tee Baffle. He explained this would reduce the amount of solids leaving the tank.

    He offered to do this for $300 plus pumping the tank again if we have the line exposed and accessible. I asked if it would be worth hiring someone to send a camera into the leech bed, and he said it would not be worth it, because it's a safe bet that underground cast iron this old is probably rusting closed and causing the blockages.

    Does this seem to be a reasonable investment for a 35 year old system based on his assessment?
    Last edited by a moderator: Nov 29, 2008
  2. leejosepho

    leejosepho DIY scratch-pad engineer

    If those clogs amounted to buildups of rust from the cast pipe, then yes, have that pipe replaced ... and if your septic tank is doing its job, there should be nothing else coming out that could cause a clog.

    All of that pumping plus the plumber's suggestion of a new baffle makes me suspicious about solids coming *out* of your tank. Opinions vary greatly about how often a septic tank should be pumped, but a tank only truly needs pumped if or when the sludge in the bottom builds up to the point of being drawn into the outlet plumbing ... and in my own experience-driven opinion, you should have one of these filters in the new outlet tee you ought to have:
    http://www.gag-simtech.com/new_files/Page566.htm

    Opinions about filters also vary greatly, but the hard fact here is that one of those inexpensive filters unfailingly serves like a parakeet in a coal mine: While also assuring no solids get through to your drain field, it will "croak" (clog) and let you know when to have your tank pumped to get rid of excessive sludge. The veteran septic man who just recently pumped my own tanks said it is time to pump when the filter needs cleaned -- replacement is *never* necessary -- after only six months.

    He definitely knows more than I, but that sounds right to me.

    Yes, absolutely!
  3. Smith333

    Smith333 Member

    Messages:
    107
    Thanks for the reply. He is not sure that the clogs were caused by rust, that was only his educated guess based on the age of the cast iron and the fact the system didn't back up again shortly after pushing the clogs into the leech field.

    The effluent filter looks like an intriguing idea. Do they really need to be cleaned in as little as 6 months? That would really suck, especially if I forgot to do it and another backup occurred. Is the particular filter you linked to something you would specifically recommend? There seem to be different designs being promoted by different companies.


    Thanks for your help.
  4. Redwood

    Redwood Master Plumber

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    Location:
    Connecticut
    I have seen filters clogged in as little as 6 months from a cleaning.
  5. leejosepho

    leejosepho DIY scratch-pad engineer

    The one I use from that link is the yellow one that simply slips down into the outlet tee and hangs there. Since installing one in each of my two tanks a couple of years ago, I have been in the habit of pulling them and rinsing them off twice each year ... but neither had never actually been clogged until just a few weeks ago, and that was because of a sludge buildup possibly caused by some other factors in one of my tanks.

    Even if your septic tank already has risers and easy-access lids, the idea of taking a few minutes every six months or so to check and possibly hose-rinse a nasty-smelling "bottle-brush" filter -- Pull it out very slowly! -- might not sound very intriguing. However, the alternative is to either pump unnecessarily in order to assure no solids get out into your drain field or else to simply wait for the drain field to fill with solids and quit working.

    As an alternative to a regular schedule for checking a filter, a high-level alarm could be installed to let you know if/when a filter begins to clog and the tank begins to become overfull, but I can much more easily afford about 15 minutes of my own time (per tank and sans parts or any other expense) twice a year.
    Last edited: Dec 1, 2008
  6. Smith333

    Smith333 Member

    Messages:
    107
    Are there any ways to predict how long a filter may last between cleanings? The tank is 1000 gallons. There's just 2 of us here, and according to the water softener we only use about 600 gallons of water per week pretty consistantly. Thanks again
  7. leejosepho

    leejosepho DIY scratch-pad engineer

    Here is what the manufacturer has to say about that:

    In my own experience, however, there is no need for scheduled replacement. For me, these filters easily rinse clean and mostly remain bright yellow.
  8. Smith333

    Smith333 Member

    Messages:
    107
    Thanks for pointing that out...not sure how I missed that. LOL I'm sold on the filter but won't be able to move forward with replacing the pipe and baffle until the soil thaws in spring.

    Anyways, while studying effluent filters I stumbled onto another issue...a lint filter for the laundry washer. Here is a link to one for $130, "Filtrol 160":

    http://www.filtrol160.com

    Any opinions on such a device? Is laundry lint really such a big contributor to leach field failure, espcially for a system that has already lasted 35 years? I appreciate all the great help so far.
    Last edited by a moderator: Dec 2, 2008
  9. leejosepho

    leejosepho DIY scratch-pad engineer

    Here is a laundry filter that might need emptied more often, but it does cost much less:
    http://www.repairclinic.com/SmartSearch/SSPartDetail.aspx?PartID=541811&PPStack=1

    The one my wife and I have here at home is similar to the high-dollar one you found, but it came from an auction for about $30.00.

    A field system that is still doing its job after 35 years was obviously designed well initially, but that does not mean it will last forever. In my own opinion, and to avoid trouble or even replacement for as long as possible, I believe every effort should be made to let nothing other than clear effluent water into a drain field. My own septic and gray water have separate fields, and I even have one of those bottle-brush filters to catch hair and whatever else from our tub drains.

    If you ever have trouble with your own field system, you might be able to at least partially revive it by installing a second field and using a diverter valve to let it remain dormant for a year or two ... then switch from one to the other every year after that and after/if the biomat dries out and shrivel-shrinks a bit.
    Last edited: Dec 2, 2008
  10. Smith333

    Smith333 Member

    Messages:
    107
    I opted to get the $130 lint filter, and after 4 loads of laundry it seems to work as advertised. I don't know if it is over priced, but if you think of it as insurance for the septic field and believe that lint is a big threat to it, it's probably worth it.

    Getting back to the septic effluent filter, I see they also sell a 6" diameter bristle filter. Would the larger diameter increase the amount of time between cleanings? Any downsides to using a larger diameter? Since we don't have a T-Baffle yet, it would be just as easy to install a 4x6 tee instead of a 4x4 tee.
  11. Redwood

    Redwood Master Plumber

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    7,450
    Location:
    Connecticut
    If a 4" line exits the tank you use a 4" tee and a 4" filter.
  12. leejosepho

    leejosepho DIY scratch-pad engineer

    I had never though of that, but yes, a 6" tee with a 4" hub for the outlet would more than double the service area of the filter.
  13. Smith333

    Smith333 Member

    Messages:
    107
    I was able to start this project last week and got the concrete distribution box exposed. I was dismayed to find that while the cover was in good condition, the side walls are crumbling, and the whole box will have to be replaced. The cast iron inlet line, as expected, is almost completely blocked with rust and other rock-hard stuff and only allows a small trickle of water into the DB. Also, the individual lines to the leach field are all at different elevations, so that the line on the right receives nearly all of the effluent. The good news is that there weren't any tree roots in the DB and the outlet lines look to be in good condition. I haven't been able to get in touch with the guy who will be performing the repairs, so I'm just wondering what folks would suggest as a replacement - another concrete DB or plastic? The current one measures 28" in diameter and 21" deep.

    Attached Files:

  14. leejosepho

    leejosepho DIY scratch-pad engineer

    A local code might specify one or the other, but either should do just fine. I would probably use a piece of 24"-round, double-wall, plastic pipe that is ribbed on the outside and smooth on the inside. Then, one 28" concrete lid can serve as a base and the other can go on top.

    A small trickle is very typical unless a bathtub or washing machine is presently dumping into the septic tank ... and if the tank and the D-box are fairly close together, replacing that line should not be very difficult.

    There is nothing terribly bad about that -- mine are the same -- and that can actually be a good thing. If just one of your lines is presently handling most or all of your load, that likely means it is in good condition and the other only has to serve as an overflow of sorts. Also, it is good for leach lines to be dormant for periods of time to dry out and "recover" a bit, so that means your second line is quite possibly in very good condition. As an experiment to see, plug the first line and let it rest for a few weeks while the other line does all the work. And since you are going to be getting a new D-box anyway, you might consider a diverter valve so you can switch lines every four or eight months (to give each line a taste of all seasons).
  15. Smith333

    Smith333 Member

    Messages:
    107
    Thanks for the reply. I discussed the situation with the master plumber who will be doing the work, and without seeing it first hand suggested placing a piece of large diameter sewer pip vertically inside the current DB, cutting holes for the inlet and outlet lines to pass through. He is concerned about digging up the old DB because it is technically part of the leach field. Hopefully he will stop out next week and clarify his approach, at which time I'll report back.

    The inlet pipe is in the process of clogging with rust again. From the looks of it, it would be completely blocked within a year. I tried to open it up a little, but the stuff inside is rock hard. At least I know all of the digging was worth while...

    Plugging the lowest outlet to test the other outlets sounds like a good idea. How would you suggest doing so? The outlet pipes are 4" corrugated flexible tubing. I'm not too keen on getting up close and personal with the effluent...
  16. leejosepho

    leejosepho DIY scratch-pad engineer

    Sure, and that is the piece of corrugated plastic I would use.

    Wearing latex gloves, being careful not to splash and washing afterward is more than I do -- I just wash afterward -- when doing something with my own system, but you will have to decide about that.

    I would probably find a couple of inexpensive, foam footballs at least an inch or two bigger than the insides of the lines for temporarily blocking them.
  17. Smith333

    Smith333 Member

    Messages:
    107
    We finally got this project taken care of. His approach was just as you suggested, inserting a 19" sewer pipe into the old distribution box and making it long enough to bring it close to the surface for future service. We filled the space caused by the difference in diameter with concrete.

    [​IMG]


    I also built a manifold so that I could use 3 of the Simtech filters in the septic tank. He'd never seen this before, but agreed to install it for me. I can't see why it won't work.

    [​IMG]
    Last edited by a moderator: May 9, 2009
  18. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    I like the idea of multiple filters!
  19. leejosepho

    leejosepho DIY scratch-pad engineer

    Even with three filters, you should still take a look at them and probably rinse them off at least once each year. That company makes a maintenance sleeve that slips down inside the tee to stop the flow before the filter is pulled, but you could easily make your own with a piece of thin-wall pipe and for a lot less money.

    Overall, nice job!
  20. Smith333

    Smith333 Member

    Messages:
    107
    Thanks. I made a sleeve like the one on the Simtech website and it works really slick. I plan on cleaning the filters just before the snow flies so I can get a sense of how fast they clog up.

    One thing that concerns me is that the filters extend so far down that there's only 2 feet of space between the bottom of the filter and the bottom of the tank. This translates to about 450 gallons of sludge capacity based on the size of my tank. I have no idea how fast the sludge builds up so that will be another variable to watch out for.
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