Septic Tank Pumping Table Shows When to Clean the Septic Tank InspectAPedia® -
Septic tank cleanout schedule - when do I pump out the septic tank?
Septic System Maintenance Guidelines
Electronic septic tank monitoring
Complete septic system care & maintenance guide, how often & how to pump out septic tanks
Septic System Life Expectancy for septic tanks, septic fields, septic pumps, etc.
Questions & answers about how often does a septic tank need to be pumped or cleaned?
Septic tank cleaning: This article provides a septic tank pumping schedule based on septic tank size and level of usage. This document explains a key point in how septic systems work: the septic tank & septic system cleaning schedule -
when to pump out the septic tank.
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We explain why a septic tank needs to be pumped regularly,
how septic tanks are cleaned, how much it costs to pump a septic tank, how to inspect and clean septic tanks safely,
what is septic tank effluent retention time, how to measure septic tank scum and sludge levels, and other septic tank maintenance advice for homeowners.
How often should septic tanks be pumped?
For an alternative method to determine when a septic tank needs to be pumped and cleaned based on inspection of the tank and measuring of the septic tank scum and sludge levels, see our article series beginning at MEASURE SCUM & SLUDGE. Or jump to What Scum Sludge Thickness = Pump Needed. For an explanation of the meaning of sewage levels in the septic tank and how that information informs septic tank pumping frequency, see SEWAGE LEVELS in SEPTIC TANKS.
If you don't know where the septic tank is located, see SEPTIC TANK, HOW TO FIND. at TANK INSPECTION PROCEDURE we describe how to inspect the septic tank before, during, and after tank cleaning operations. Septic system maintenance and repair are discussed in a collection of detailed articles listed at Septic Tank and Septic System Maintenance. Also see SEPTIC TANK PUMPING PROCEDURE, our detailed step by step photo-illustrated guide to find, pump and clean a septic tank. See Septic Backup Prevention for tips to avoid a septic problem during times of anticipated heavy septic system usage.
Citation of this article by reference to this website and brief quotation for the sole purpose of review are permitted. Use of this information at other websites, in books or pamphlets for sale is reserved
to the author. Technical reviewers are invited and are listed at "References."
SEPTIC TANK PUMPING SCHEDULE - A Guide to Septic Cleaning - How Often Do You Pump Out A Septic Tank?
Table I below lists the recommended septic tank pumping frequency according to septic tank capacity and household size. The frequencies were calculated to provide a minimum of 24 hours of wastewater retention assuming 50 percent digestion of the retained solids.
The removal of septic waste by cleaning the septic tank is a critical step in septic system care as it extends the life of the septic field. Even if you don't care
how septic systems work you need to know when to clean the septic tank by pumping out septic waste. Look up your tank size and number
of building occupants to see how often the septic tank should be cleaned.
Table I. Septic Tank Pumping Frequency in Years
.
Household size - Number of Occupants
.
1
2
3
4
5
6
7
8
9
10
Tank-Gallons
Septic Tank Pumping Frequency in Years
500*
5.8
2.6
1.5
1.0
0.7
0.4
0.3
0.2
0.1
--
750*
9.1
4.2
2.6
1.8
1.3
1.0
0.7
0.6
0.4
0.3
900
11.0
5.2
3.3
2.3
1.7
1.3
1.0
0.8
0.7
0.5
1000
12.4
5.9
3.7
2.6
2.0
1.5
1.2
1.0
0.8
0.7
1250
15.6
7.5
4.8
3.4
2.6
2.0
1.7
1.4
1.2
1.0
1500
18.9
9.1
5.9
4.2
3.3
2.6
2.1
1.8
1.5
1.3
1750
22.1
10.7
6.9
5.0
3.9
3.1
2.6
2.2
1.9
1.6
2000
25.4
12.4
8.0
5.9
4.5
3.7
3.1
2.6
2.2
2.0
2250
28.6
14.0
9.1
6.7
5.2
4.2
3.5
3.0
2.6
2.3
2500
30.9
15.6
10.2
7.5
5.9
4.8
4.0
3.5
3.0
2.6
NOTES to the Septic Tank Pumping Schedule Table:
Numbers in the septic pumping table indicate septic treatment tank pump out in frequency of every nn years for conventional septic tanks, and
assuming for year-round occupancy of the residence. (This data does not pertain to simple holding tanks which
retain all solid and liquid waste with no treatment no effluent disposal system.)
* These septic tank sizes are below the minimum size allowed in Pennsylvania and other jurisdictions. Florida septic tank pumping rules and Ohio septic tank
cleaning rules may be more demanding.
Minimum septic tank sizes: Under current Pennsylvania law a 900 gallon septic tank is the minimum size that must be used for a home with
three bedrooms or less. If six people reside in a three-bedroom house, the tank should be pumped every 1.3 years.
If the same system serves a family of two, the tank would be ready for pumping every 5.2 years. Systems installed
before the current rules and regulations were implemented may need to be pumped more often, perhaps every year or less.
Garbage disposers will increase the frequency of pumping. For example, if this same three bedroom house with six residents had a garbage disposal and was generally producing a higher volume of wastewater, the pumping frequency would be calculated as follows:
1.3 years - [(0.2) x 1.3 years] = 1.0 year. For more analysis of the effect of garbage disposers on septic systems see Garbage Grinders or Garbage Disposes and Septic Tank Maintenance
Typical Septic Tank Pumping Costs: A typical fee to pump a septic tank is $200. to $300 to pump a septic tank up to 1000g in size, provided
that the tank pumping access port has been uncovered and is readily accessible. If the septic pumping contractor needs to find the septic tank
and then excavate the septic tank pumping access opening, expect to pay an additional $350. to $400. provided that no extraordinary measures
are needed. Prices vary somewhat by region. A part of the fee you're paying your septic pumping contractor is the cost to dispose of
the septage.
For an explanation of the meaning of sewage levels in the septic tank and how that information informs septic tank pumping frequency, see SEWAGE LEVELS in SEPTIC TANKS.
Onsite sewage disposal system holding tanks, where there is no septic field, will need to be pumped
more frequently based simply on the rate and volume of septic waste inflow.
Portions of this information were provided by the Penn State College of Agriculture - Cooperative Extension.
We have edited and added to the original septic tank pumping guideline material based
on research and field experience testing, inspecting, and installing septic systems and based on study of other reference sources
on septic system maintenance and design.
Electronic Monitors for Septic Tank Scum & Sludge Levels
Below at References we also describe an electronic septic tank monitor or grease trap monitor from Worldstone. These devices can track sludge, scum, or grease levels in order to best schedule septic tank pumping or grease trap cleaning. This product is suitable for commercial installations and possibly for some residential septic tank systems.
According to the company, "Data from monitors can help establish appropriate service intervals, and document maintenance for regulatory compliance. Alarm features can help detect abnormal conditions and prevent costly backups."The company also produces an oil tank level monitor.
OPINION - DF: this product is a great idea for commercial installations or problem septic installations. Substituting actual septic tank scum layer thickness or scum level thickness data for the septic tank pumping schedule table above may allow the tank to be opened and pumped less often - saving some money.
Watch out: But don't forget that regular opening and inspection of the septic tank, such as happens when the septic tank is to be pumped out or "cleaned", gives an additional opportunity to check for other septic system problems that could be leading to a costly failure, but that don't directly concern the septic tank sludge or scum layer thickness. Examples include the discovery of lost or damaged septic tank baffles, septic tanks leaks that allow ground water to flood the septic system, or septic tank leaks out of the tank.
Frequently Asked Questions (FAQs) about the pumping or cleanout schedule for septic tanks
Question: Recent Septic System Repair / Pumpout
I had some work done recently and if I sent a picture of the work, can you give me an idea of the quality of work? BTW, I love your site. - Syd
Reply:
A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem. And certainly from a photograph alone one can't make a full nor accurate evaluation of the condition of a septic system.
That said, I'll be glad to look at your photos and if the initial Q&A is sufficiently modest I will reply pro-bono. Of course as you gave no information about the topic, I can't say in advance how much I can comment on the pictures.
Reader comment - followp:
I appreciate it. I used the information extensively when I bought this house. It is what clued me into the FPE panel I had and why when walking on the floor above the panel, the lights would sometimes dim (the breaker for the water heater was loose and arcing to the bus bar). I replaced the panel, breakers, etc..
Here are the specifics:
Built in ‘84, in TN
4 BR, 2 bath, split foyer.
Just my wife and I live here. Previous owners had 5 kids.
The washing machine is on a proper grey water disposal system. The dish washer will be added soon.
Here's the story.
What started out 2 Friday's ago with a day off, I called the honey wagon to pump the tank. I have lived here for nearly 4 years and when I bought the house, the previous owners had the tank “inspected” and were informed that the tank did not need to be pumped. They lived here for 7 years and never had it pumped or checked. Now, the truck shows up and we start digging. Turns out that its not possible that the people that the previous owners had check the could have. The amount of dirt disturbed vs what I had to dig was way off. So the truck leaves and I dig a hole that is 5 feet deep by 4ft by 3 ft. By hand.
Fast forward to yesterday, truck comes back and we open the lid. This is when we find out that its approximately 2000 gal precast cement tank with 3ea 2.5x4ft hatches. Apparently this is rather uncommon around here. Also find that the exit baffle is nearly disintegrated however still in place. There was not an input baffle, in fact, it was a pipe that just poured waste onto the surface. The scum layer was 5 to 8 inches thick. I do not know how thick the sludge was, I had to go to home depot to get some pipe. Also, the input was right next to the output.
The driver pumped as much as he could (truck filled, he was expecting a 1000 gal tank which is common in this area), he got most the sludge and scum, 2/3 total volume removed. He recommended that a piece of pipe 2 ft. long be added to the input and to add a 4 in pipe with a tee on it. His method for installing the tee was to use PVC cement to a 2 ft long pipe, stuff the pipe down the output and secure with expanding polyurethane (great stuff) foam. You can see all of this in the picture. The pipe leaving to the drain field is orangeburg.
Here is what I think I know to be true:
The tank was never correctly installed. I should have had the input moved and a tee or baffle installed. I should have asked him to come back to pump the rest of the liquid. I need to replace the orangeburg pipe soon.
So here are my questions:
Since the system has been running like this 27 years and not pumped in at least 11 (could be 27 as well), do you think ill get another 10, maybe 20 out of it? Since the tank is rather oversized and its only the two of us, I think its safe to say the system is not taxed that much. We put a half gallon of spoiled buttermilk down the drain each month.
Thank you again for your assistance and for providing such an informative site with ACCURATE information. Feel free to use my picture of a hall of shame or whatnot.
Reply: Buttermilk is not a useful treatment to add to a septic tank
About your note and photo - just in order of thoughts & your note:
7+4=11 years, probably longer than recommended for pumping the septic tank - see http://www.inspectapedia.com/septic/tankpump.htm
2000 gal precast cement tank with 3ea 2.5x4ft hatches - probably a good tank, certainly decent size; if the liquid/sewage levels were normal then the tank is not cracked, damaged, leaking.
It would have been better to pump the whole tank out completely - we don't know really if the sludge was adequately removed from tank bottom, though it's possible for the pumper to probe and measure the sludge thickness that remained.
It was absolutely correct to add the tee at the inlet - it reduces sewer gas and sewage backflow into the incoming sewer line; I'm not experienced with using expanding foam to secure the tee
if it works both to hold the tee in place AND there is no groundwater leaking INTO the tank at that end, you're in good shape.
YOU SHOULD open the OUTLET end of the tank and be sure that there is an outlet tee in place - this is critical to avoid sending solids into (and ruining) the drainfield
Orangeburg pipe: old, very old, questionable condition; I'd like to see any photos if you dig up any of that material.
If you find there was no outlet tee, combined with infrequent pumping and orangeburg pipe, you will want to be saving/planning for drainfield repair/replacement.
Inspect the septic drainfield area for wet spots, smells, evidence of failure.
Minimum steps:
make sure there is an outlet tee
inspect for evidence of field failure
plan for field replacement
Desirable:
finish pumping the tank; as you need to open it again to see the outlet tee side, that's an opportunity for the pumper to finish cleaning, though usually we see them pump from the center access if that's accessible
install a septic riser over the center access port so that on next pumpout schedule you can clean the septic tank without so much digging.
I can't for sure predict how much life remains - a lot depends on level of usage, soil conditions. I've mentiond the tee - a predictor of field failure if it was missing.
Buttermilk is not a useful septic system treatment, though it won't hurt anything. You don't need to treat the system and in fact some treatments are harmful, even illegal. See http://www.inspectapedia.com/septic/septadds.htm
Reader follow-up comment:
I think I may have been misleading. The input from the house is the 3 inch pipe towards the top of the picture (under the shovel). It originally was just a 3in 90 that poured onto the top of the surface. The outlet is the field is the 4in tee. The input is now under the scum layer and does not have a tee. My picture shows what should be the output, however, when installed it appears that the contractor put the input on that side as well.
Questions & Answers regarding this article
Questions & answers about how often does a septic tank need to be pumped or cleaned?
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Additional technical contributors & reference sources for this article are listed below.
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"Estimated Septic Tank Pumping Frequency," Karen Mancl, 1984. Journal of Environmental Engineering. Volume 110.
"The Soil as a Treatment System." Tyler, E. T., R. Laak, E. McCoy, and S. S. Sandhu, Home Sewage Treatment. ASAE publication 5-77, 1977.
Thanks to reader Robert Shirley, Calgary, for discussing alternative ways to measure septic tank sludge, including the relatively low cost electronic system on the market from Worldstone Inc. (SepticWatch) - a system to monitor sludge and scum and grease levels in grease traps or septic tanks - 04/20/2010
Worldstone, http://www.worldstoneinc.com/ electronic monitors, including via internet, for grease traps, septic tanks, oil tanks - manufactured by F.O.G. Solutions, 1348 Delta Drive, Saginaw, MI 48638, 866 279-2824, 989-928-1806, Fax 480-247-4983
"Worldstone Inc. is a Braintree Massachusetts based company that specializes in separation tank monitoring. Using established ultrasonic technologies, Worldstone’s GREASEwatch, SEPTICwatch and OILwatch monitors capture critical tank information and transfers data to city officials, end users or service providers creating a safer, cost effective solution to manual inspections. Data from monitors can help establish appropriate service intervals, and document maintenance for regulatory compliance. Alarm features can help detect abnormal conditions and prevent costly backups.
Worldstone monitors are currently assisting over 200 major restaurants, hospitals, prisons, casinos and city officials across the United States." Septic Tank Monitoring:
"The SEPTICwatch monitor provides continuous monitoring of the sludge, scum, temperature and liquid levels [in a septic tank]. ... real-time information on actual changes as a percentage of permissible floating solids, bottom solids and total solids. It also provides the immediate status of the liquid level within the tank in inches. Using the monitor's programmable Control Unit, the tank's optimum level for pumping is set, so the tank can be pumped when it's actually needed. The [septic tank] monitor's Control Unit can also be programmed to warn of dangerously high solid levels and lower than normal/higher than normal liquid levels - emergency conditions that could indicate system failure."
Grease Trap Monitoring: "...GREASEwatch monitor uses ultrasonic transducers and an embedded microprocessor to continuously monitor the sludge, scum, liquid levels and temperature in your grease trap. ... get real-time information on incremental changes in the levels of floating solids, bottom solids and total solids at the touch of a button. ... the immediate status of the liquid level in the trap in inches. The Control Unit can be programmed to indicate how full the tank should be before pumping, so there's no more guessing when it's time for service. The GREASEwatch monitor lets you plan a pumping level that meets your needs and protects your investment."
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
Advanced Onsite Wastewater Systems Technologies, Anish R. Jantrania, Mark A. Gross. Anish Jantrania, Ph.D., P.E., M.B.A., is a Consulting Engineer, in Mechanicsville VA, 804-550-0389
(2006), Advanced Onsite Wastewater Systems Technologies.
Outstanding technical reference especially on alternative septic system design alternatives. Written for designers and engineers, this book is not at all easy going
for homeowners but is a text we recommend for professionals--DF.
AEROBIC SEPTIC SYSTEMS
Builder's Guide to Wells and Septic Systems, Woodson, R. Dodge: $ 24.95; MCGRAW HILL B; TP;
Quoting from Amazon's description: For the homebuilder, one mistake in estimating or installing wells and septic systems can cost thousands of dollars. This comprehensive guide filled with case studies can prevent that. Master plumber R. Dodge Woodson packs this reader-friendly guide with guidance and information, including details on new techniques and materials that can economize and expedite jobs and advice on how to avoid mistakes in both estimating and construction. Chapters cover virtually every aspect of wells and septic systems, including on-site evaluations; site limitations; bidding; soil studies, septic designs, and code-related issues; drilled and dug wells, gravel and pipe, chamber-type, and gravity septic systems; pump stations; common problems with well installation; and remedies for poor septic situations. Woodson also discusses ways to increase profits by avoiding cost overruns.
Country Plumbing: Living with a Septic System, Hartigan, Gerry: $ 9.95; ALAN C HOOD & TP;
Quoting an Amazon reviewer's comment, with which we agree--DF:This book is informative as far as it goes and might be most useful for someone with an older system. But it was written in the early 1980s. A lot has changed since then. In particular, the book doesn't cover any of the newer systems that are used more and more nowadays in some parts of the country -- sand mounds, aeration systems, lagoons, etc.
Design Manuals for Septic Systems
US EPA Onsite Wastewater Treatment Systems Manua [online copy, free] Top Reference: US EPA's Design Manual for Onsite Wastewater Treatment and Disposal, 1980, available from the US EPA, the US GPO Superintendent of Documents (Pueblo CO), and from the National Small Flows Clearinghouse. Original source http://www.epa.gov/ORD/NRMRL/Pubs/625R00008/625R00008.htm Onsite wastewater treatment and disposal systems,
Richard J Otis, published by the US EPA. Although it's more than 20 years old, this book remains a useful reference for septic system designers.
U.S. Environmental Protection Agency, Office of Water Program Operations; Office of Research and Development, Municipal Environmental Research Laboratory; (1980)
"International Private Sewage Disposal Code," 1995, BOCA-708-799-2300, ICBO-310-699-0541, SBCCI 205-591-1853, available from those code associations.
"Manual of Policy, Procedures, and Guidelines for Onsite Sewage Systems," Ontario Reg. 374/81, Part VII of the Environmental
Protection Act (Canada), ISBN 0-7743-7303-2, Ministry of the Environment,135 St. Clair Ave. West, Toronto Ontario M4V 1P5 Canada $24. CDN.
Manual of Septic Tank Practice, US Public Health Service's 1959.
Onsite Wastewater Disposal Books
Onsite Wastewater Disposal, R. J. Perkins;
Quoting from Amazon: This practical book, co-published with the National Environmental Health Association,
describes the step-by-step procedures needed to avoid common pitfalls in septic system technology.
Valuable in matching the septic system to the site-specific conditions, this useful book will help you install a reliable system in
both suitable and difficult environments. Septic tank installers, planners, state and local regulators, civil and sanitary engineers,
consulting engineers, architects, homeowners, academics, and land developers will find this publication valuable.
Onsite Wastewater Treatment Systems, Bennette D. Burks, Mary Margaret Minnis, Hogarth House 1994 - one of the best septic system books around, suffering a bit from small fonts and a weak index. (DF volunteers to serve as indexer if Burks/Minnis re-publish this very useful volume.)While it contains some material more technical than needed by homeowners, Burks/Minnis book on onsite wastewater treatment systems a very useful reference
for both property owners and septic system designers. We refer to it often.
While Minnis says the best place to buy this book is at Amazon (our link at left), you can also see this book at Minnis' website at http://web page .pace.edu/MMinnisbook
Septic Tank/Soil-Absorption Systems: How to Operate & Maintain [ copy on file as /septic/Septic_Operation_USDA.pdf ] - , Equipment Tips, U.S. Department of Agriculture, 8271 1302, 7100 Engineering, 2300 Recreation, September 1982, web search 08/28/2010, original source: http://www.fs.fed.us/t-d/pubs/pdfimage/82711302.pdf
Planting Over Septic System Component", Daniel Friedman (author/editor, InspectAPedia.com), The Innovator, Winter/Spring 2008, BCOSSA, British Columbia OnSite Sewage Association, 201-3542 Blansard St., Victoria BC V8X 1W3 Canada
Septic System Owner's Manual, Lloyd Kahn, Blair Allen, Julie Jones, Shelter Publications, 2000 $14.95 U.S. - easy to understand, well illustrated, one of the best practical references around on septic design basics including some advanced systems; a little short on safety and maintenance. Both new and used (low priced copies are available, and we think the authors are working on an updated edition--DF.
Quoting from one of several Amazon reviews: The basics of septic systems, from underground systems and failures to what the owner can do to promote and maintain a healthy system, is revealed in an excellent guide essential for any who reside on a septic system. Rural residents receive a primer on not only the basics; but how to conduct period inspections and what to do when things go wrong. History also figures into the fine coverage.
Test Pit Preparation for Onsite Sewage Evaluations, State of Oregon Department of Environmental Quality, Portland OR, 800 452-4011. PDF document. We recommend this excellent document that offers detail about soil perc tests, deep hole tests, safety, and septic design. Readers should also see Soil Percolation Tests and for testing an existing septic system, also see Dye Tests
Grass is Always Greener Over the Septic Tank, Bombeck, Erma: $ 5.99; FAWCETT; MM;
This septic system classic whose title helps avoid intimidating readers new to septic systems, is available new or used at very low prices.
It's more entertainment than a serious "how to" book on septic systems design, maintenance, or repair. Not recommended -- DF.
US EPA Onsite Wastewater Treatment Systems Manual Top Reference: US EPA's Design Manual for Onsite Wastewater Treatment and Disposal, 1980, available from the US EPA, the US GPO Superintendent of Documents (Pueblo CO), and from the National Small Flows Clearinghouse. Original source http://www.epa.gov/ORD/NRMRL/Pubs/625R00008/625R00008.htm
Water Wells and Septic Systems Handbook, R. Dodge Woodson. This book is in the upper price range, but is worth the cost for serious septic installers and designers.
Quoting Amazon: Each year, thousands upon thousands of Americans install water wells and septic systems on their properties. But with a maze of codes governing their use along with a host of design requirements that ensure their functionality where can someone turn for comprehensive, one-stop guidance? Enter the Water Wells and Septic Systems Handbook from McGraw-Hill. Written in language any property owner can understand yet detailed enough for professionals and technical students this easy-to-use volume delivers the latest techniques and code requirements for designing, building, rehabilitating, and maintaining private water wells and septic systems. Bolstered by a wealth of informative charts, tables, and illustrations, this book delivers: * Current construction, maintenance, and repair methods
* New International Private Sewage Disposal Code
* Up-to-date standards from the American Water Works Association
Wells and Septic Systems, Alth, Max and Charlet, Rev. by S. Blackwell Duncan, $ 18.95; Tab Books 1992. We have found this text very useful for conventional well and septic systems design and maintenance --DF.
Quoting an Amazon description:Here's all the information you need to build a well or septic system yourself - and save a lot of time, money, and frustration. S. Blackwell Duncan has thoroughly revised and updated this second edition of Wells and Septic Systems to conform to current codes and requirements. He also has expanded this national bestseller to include new material on well and septic installation, water storage and distribution, water treatment, ecological considerations, and septic systems for problem building sites.
The NSFC Products List has an excellent list of design manuals/modules available from their website or by telephone 800-624-8301
Submissions welcome. send us a suggested document link or request an exchange of website links
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