Interval for pumping septic tank

Old 11-11-18, 10:15 AM
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Interval for pumping septic tank

My home was built in 1990 and the septic tank (1000 gallons) was pumped in 2005. The sludge/scum levels in the tank were measured this year and show virtually no scum and less than 8" of sludge. Based on this buildup of waste over 13 years, it would appear the need to pump the tank should be another 26 years in the future given the same future usage as there has been for the past 13 years.

The above estimate is based on the following premise: Sludge should not exceed 24" and water between sludge and scum should be no less than 24" apart.

A 39 year pumping interval will sound ridiculous to people in the business of pumping these tanks.

Is there any real reason I should pump this tank until the above intervals are reached? I do have a riser over the clean-out port that allows inspection of the tank with minimum work so I can check the levels easily

PS: I have a dry well for all clothes washing water and this water can be diverted into the septic tank with the closing of a gate valve should there be someone here washing soiled diapers..
Old 11-11-18, 10:34 AM
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Doesn't your local jurisdiction specify the interval? It's usually 2-4 years for us. Maybe the size makes a difference.
Old 11-11-18, 11:38 AM
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A new filed is only $20K so if you think saving a couple of hundred dollars every 3-5 years is a good gamble then go for it!

It never hurts to over pump but under pumping can get expensive!
Old 11-11-18, 02:24 PM
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Based on my situation, at 5 years I would have had less than 5" of sludge. Do you really think that is the right time to have pumped this system?

Response to prior question about local requirement: No, there is no government mandated requirement for my area.
Old 11-11-18, 03:57 PM
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Actually, it is not unusual to evaluate the estimated future buildup of sludge just after a pumping to determine when to do the next pumping. If usage changes, for example another person comes to live in the house, you should shorten the time to the next pumping.

But you should plan on the next pumping before the critical level of sludge is actually reached, to allow for possible errors in judgment.
Old 11-12-18, 02:52 AM
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I go out and rinse my outlet filter off twice a year (Spring and Fall). When I do it in the Spring, I also stick a 5 Foot probe down my observation port and "feel" for the where the sludge layer begins. Last Spring, for example, it was only 13" or 14" from the bottom. I haven't had this 1000 gallon tank pumped since 2002 (only twice since it was installed in 1987).

I guess I'm glad the People's Republic of Vermont hasn't yet started to mandate the Septic Tank pumping frequency . . . . situations and usage patterns vary.

Last edited by Vermont; 11-12-18 at 03:19 AM.
Old 11-12-18, 03:22 AM
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While it's not something I'd recommend, I went 26 yrs before my tank was pumped the first time .... because I couldn't find a pumper that was willing to come up my driveway, and then the one I got said he woudn't come back. We were pleasantly surprised with the amount of sludge in the tank. I have always worked to limit what goes thru the system [kitchen sink and laundry don't go into the tank] I also add yeast to the tank about every other month.

As the others have said, it's better to over pump than not pump often enough!

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