Septic holding tank guide:

This document discusses holding tanks in septic system design applications.

US EPA information has been expanded upon with supplemental documentation, references, and comments.

What are septic holding tanks, how, where, and why are they used?

Holding Tank Septic Systems use a sealed tank to hold household waste and wastewater until the tank can be pumped out by a septic pumping company.

Most jurisdictions do not permit septic holding tanks as a permanent wastewater handling method for full-time occupied residences, but holding tanks may be permitted during new home construction and in other special cases.

Our photo shows a worker emptying a septic holding tank in the San Marco area of Venice, Italy, in June 2017.

Traditionally Venice's sewer system emptied into the city's canals, and much of it still does, relying on tidal action to keep the canals acceptably clean.

A photo of the septic tank pumper boat or sewage boat is discussed

at PUMPER TRUCKS & VACUUM PUMPS SOURCES / SPECS.

In New York State we've seen holding tank systems in use on small-lot properties located along the Hudson River. Generally such systems will not be acceptable for full time occupied residences as even a large tank of several thousand gallons will require frequent and costly pumping and disposal.

Holding Tank Septic System Regulations for Installation and Use

The use of holding tanks shall not be permitted for new home construction except where occupancy of a home is permitted while the sewage treatment system is under construction.

Tank size shall be based upon five days design flow or 1,000 gallons, whichever is greater and meet the same construction as a septic tank except that the holding tank shall not have an outlet.

Holding tanks are not acceptable for long term use on year-round residences [in most jurisdictions -Ed].

The above sanitary code citation is from: New York State Appendix 75-A.10 OTHER SEPTIC SYSTEMS

Septic Holding Tanks and Septic Hauling Systems

Photo: a septic tank being pumped in Two Harbors, MN. Contact information for the pumping company, David Roeder, Superior Septic Service, and their pumper truck are shown

at PUMPER TRUCKS & VACUUM PUMPS SOURCES / SPECS.

Onsite Wastewater Treatment Systems Special Issues Fact Sheet 4 EPA 625/R-00/008

Description of Septic Holding Tank Systems

A septic holding tank or vault or "tight tank" receives wastewater from a home or commercial establishment and stores it until it is pumped out and hauled to a receiving/processing facility. Although similar to septic tanks, septic vaults have no outlet piping and must be watertight.

The volume can range from 1,000 gallons to 4,000 gallons or more. The vault should be equipped with an audible and visible high-water alarm, which alters the resident to the need for pumping.

Different sizes of vaults and tank trucks can be used; water conservation can reduce costs considerably by reducing the frequency of pumping. A vault can be equipped with a standpipe and a quick disconnect to which the pumping truck can be directly connected for efficient (minimal spillage) emptying of the vault.

Holding tanks can be used for the entire wastewater flow in cases where conventional and typical alternative systems are not feasible. They are often used this way for seasonal homes in sensitive environmental settings. Holding tanks can also be used to collect only a part of the wastewater flow. Usually, they are used to collect the greywater when non-water-carriage toilets are employed in sensitive areas.

This option permits a significant reduction (usually one-third or more) in the number of tank pumpings as compared to the whole wastewater collection option. Another holding tank option is to collect only the blackwater fraction of the wastewater while the graywater is treated in an OWTS.

This option is most popular in estuarine areas where significant nitrogen removal is required because the blackwater may contain from 70 to 90 percent of the total nitrogen load. In this case the reduction in pumping frequency from the whole wastewater option would be about two-thirds.

Over and above these combinations a program to reduce water use can be overlaid. The critical contribution of such a program (see chapter 3) is to reduce the daily volume of wastewater (blackwater, graywater, or combined) produced and the required frequency of holding tank pumping.

Some onsite wastewater recycling can be added to this program in arid regions where gravity feed and belowground watering of non consumable vegetation can be accomplished. However, such a program must meet all local public health requirements.

Applications of Septic Holding Tank Systems

Pump and haul collection is best used when soil absorption fields do not work (for example, where bedrock or ground water levels are near the ground surface) and there is no sewer system.

Typical applications are second homes, where annual occupancy may be only a few days to a few months; where a nuisance or public health hazard must be abated; where an isolated building has no running water; in temporary structures or gathering places; or where nutrients must be excluded from ground water to protect environmentally sensitive areas.

Pump and haul collection may also simply be the least expensive alternative in some places.

Pump and haul systems are viable only under a wastewater authority that guarantees service. Pump and haul collection can became prohibitively expensive when homes are occupied all the time or where the distance from the treatment plant to the home is more than a few miles.

Management needs of Septic Holding Tank Systems

Holding tanks should be used only where a proper management program is in place. Construction requirement are essentially the same as for a septic tank in that the onsite testing for tank leakage is vital to a successful design and the alarm system must be dredged for proper functioning before acceptance.

In addition to timely pumping, operation and maintenance requirements should include checking the alarm function, cleaning the activation floats, and comparing volume used vs. volume accumulated in the tank.

The skill requirements at the site are minimal and can be estimated as approximately 1 hour per pumping. There are normally no energy requirements; the residuals are the tank contents, and confined-space entry safety requirements must be followed if tank entry is required.

Risk management issues of Septic Holding Tank Systems

Holding tanks are not subject to upset by flow variation, toxic loads or power outages. They should be insulated and possibly heat-treated in extremely cold climates.

If properly vented through the building sewer, they should not exhibit odor problems, but use in hot climates may require an increase in pumping frequency or a regular addition of lime for mitigation. There is a release of objectionable odors during tank pumping, which can cause some discomfort to residents.

Costs of Septic Holding Tank Systems

More recent cost estimates for holding tank-hauling wastewater disposal indicate that tank installation is about $1 per gallon of capacity (up to 5,000 gallons) while the alarm system is about $400.

Tank pumping is generally in range of 10 to 30 cents per gallon, to which labor, travel and equipment amortization may be added (or these costs may be included in a flat fee). Travel costs will dominate if the round-trip distance to the holding tank, to the disposal site, and back to home base exceeds 50 miles.

The permit costs to discharge the sewage removed from a septic holding tank at an appointed site (treatment plant, land spreading site, or independent treatment facility) is also escalated, multiple pumping from a year-round house can become extremely expensive.

Contributor

Additional thanks to David Roeder, Superior Septic Service, 524 4th Ave., Two Harbors, MN 55616, USA, Tel: 218 834-6969 for discussion of septic tank pumping procedures, distances, hoses, and levels. May 2017.

Holding Tank Septic System Design References & Product Sources

Illustration: the PA DEP illustrates the difference between a holding tank and a septic tank - cited in detail below.

• Anderson, C.D. 1986 Trucked Collection Systems Experience in the Northwest Territories. In Proceedings of Appropriate Wastewater Management Technologies for Rural Areas Under Adverse Conditions. Technical University of Nova Scotia, Halifax, NS.
• Burrows, R., and N. Bouwes. The Cost of Holding Tanks for Domestic Wastewater. Small Scale Waste Management Report. University of Wisconsin, Madison, WI.
• Dix, S.P. Case Study Number 4: Crystal Lakes, Colorado. National Small Wastewater Flows Clearinghouse, West Virginia University, Morgantown, WV.
• Mahoney, W.D., ed.-in-chief. 1989. Means Site Work Cost Data. R.S. Means Co., Kingston, MA.
• Mahoney, W.D., ed.-in-chief. 1990. Means Site Work Cost Data. R.S. Means Co., Kingston, MA.
• Manci, K. No date. Wastewater Treatment Alternatives.Holding Tanks. The Pennsylvania State University, College of Agriculture, Cooperative Extension Service, University Park, PA.
• Mooers, J.D., and D.H. Waller. 1996. Onsite Wastewater Research Program: Phase III. TUNS/Centre for Water Research Study, Halifax, NS.
• National Association of Waste Transporters (NAWT). 1998. Introduction to Proper Onsite Sewage Treatment. National Association of Waste Transporters, Scandia, MN.
• NY RESIDENTIAL ONSITE WASTEWATER TREATMENT SYSTEMS DESIGN HANDBOOK (2012), New York State Department of Health, Health Education Services, POB 7126, Albany NY 12224 Tel: 518-439-7286 - retrieved 2022/06/22 original source: https://www.health.ny.gov/environmental/water/drinking/wastewater_treatment_systems/docs/design_handbook.pdf
  Excerpt:
  The use of holding tanks shall not be used for new residential construction regardless of full-time or part-time occupancy, except when temporary occupancy of a dwelling is allowed while the OWTS is under construction or when installation is delayed due to weather conditions (such as freezing temperatures or excessive rain).
  
  Holding tanks are only intended to meet the above noted exception or to correct existing failing OWTS when no other alternative exists.
  
  Holding tanks are not deemed acceptable for long-term use at year-round residences due to high maintenance costs and continuous operation attention.
  
  If considered on a permanent basis due to extreme hardship to replace a failed system and no other options are available, approval may be required by the local code enforcement official (CEO), LHD or other agency having jurisdiction. Tank size shall be based upon a minimum of five (5) days design flow or 1,000 gallons, whichever is greater, and meet the same construction standards as a septic tank except that the holding tank shall not have an outlet.
  
  The holding tank must be designed, installed and maintained in a way that promotes ease of access for pumping and cleanup. Holding tanks should be provided with access to grade. The access should be provided with a cover that is water tight and lockable to prevent inappropriate or unapproved access.
  
  Holding tanks may need to be properly vented through the house vent stack to avoid odor issues and related nuisances.
  
  All holding tanks shall be equipped with an alarm (audible and visual) located in a conspicuous place to indicate when pump out is necessary. The owner should have a contract for service with a NYSDEC permitted septage waste transporter to pump the holding tank as needed.
  
  A solenoid valve on the water service line to the household (upstream of all fixtures and immediately downstream of a hydropneumatic tank, if one exists) should also be considered to avoid holding tank overflows.
  
  Water saving fixtures should be installed and water saving practices should be implemented in any home being
served by a holding tank to minimize pump out maintenance costs. Waste management districts or RMEs are recommended for areas with numerous holding tanks to provide continuous inspection and maintenance services.
• Ohio, OUTHOUSES & HOLDING TANKS REGULATIONS, [PDF] Ohio Department of Health, retrieved 2017/10/20, original source: http://www.odh.ohio.gov/
• Pennsylvania, ACT 537: UNDERSTANDING HOLDING TANKS [PDF] Pennsylvania Department of Environmental Protection (DEP) - retrieved 2022/06/22 original source: https://www.harmony-township.org/wp-content/uploads/2017/04/ACT-537-UNDERSTANDING-HOLDING-TANKS.pdf
  Excerpts:
  As defined in the Department of Environmental Protection (DEP) regulation 25 Pa. Code §73.1, a holding tank is “a tank, whether permanent or temporary, to which sewage is conveyed by a water carrying system.”
  
  Further, it is “a watertight receptacle that receives and retains sewage and is designed and constructed to facilitate ultimate disposal of sewage at another site.”
  
  This section of DEP’s regulations, as well as others, is available on The Pennsylvania Code website. http://www.pacode.com/
  
  Holding tanks (Figure 1) and septic tanks (Figure 2) are very different structures. Again referring to 25 Pa. Code §73.1, a septic tank is “a treatment tank that provides for anaerobic (oxygen-poor conditions) decomposition of sewage prior to its discharge to an absorption area.”
  
  This treatment function is the first of two major differences between a septic tank and a holding tank.
  
  Holding tanks do not treat sewage; they merely store sewage that will be treated at another location.
  
  The second difference is that septic tanks discharge partially treated sewage (called effluent) into the soil for final treatment through an outlet.
  
  Holding tanks have no such outlet.
• SEPTIC SYSTEM DESIGN: ONSITE WASTEWATER TREATMENT SYSTEMS MANUAL [PDF] (2002) EPA 625/R-00/008, U.S. EPA, Office of Water Office of Research and Development U.S. Environmental Protection Agency retrieved (new) 2019/09/18 original source: https://www.epa.gov/sites/production/files/2015-06/documents/2004_07_07_septics_septic_2002_osdm_all.pdf
• U.S. Environmental Protection Agency (USEPA). 1984. Final Generic Environmental Impact Statement: Wastewater Management in Rural Lake Areas. U.S. Environmental Protection Agency, Region 5, Chicago, IL.
• US EPA DESIGN MANUAL FOR ONSITE WASTEWATER TREATMENT AND DISPOSAL
• Waller D.H., and A.R. Townshend. 1987. Appropriate Wastewater Management Technologies for Rural Areas Under Adverse Conditions. Special Publication, Technical University of Nova Scotia, Halifax, NS.

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Our lakehome has just a septic holding tank. Will there be just one tank?

We own a lake home with a holding tank.

We thought it was a septic when we purchased the home but our septic man told us it was a holding tank when he came to pump it out.

We have it pumped regularly but we only see one tank. Is there a second tank?

How would we find it, if so? We see no holes, pipes, nothing going into this tank when it's open for cleaning.

Also, our home was built in 1962. Is there any way to get the sewer & drain plots for this house? And, are holding tanks legal for a permanent residence? (May 16, 2014) Fran

Reply:

Fran, your local building department might have plans on file, but often those agencies don't.

Even if there was a filed plan, we can't know if the plan shows what was approved or instead, what was actually built. Nor do we know what repairs or changes may have rearranged things in the intervening decades.

This article shows how to find buried septic tanks and piping

SEPTIC TANK, HOW TO FIND

Is a closed vault septic the same thing as a septic holding tank?

We were told we have a closed vault septic system; Is that the same as a holding tank that is periodically pumped out? On 2022-06-22 by Anastasia

by InspectApedia-911 (mod) - Yes; here's the definition of a closed vault septic system

@Anastasia,

Thanks for the helpful question.

Definition of "closed vault septic system" =

a septic holding tank that is a water-tight, closed container that stores incoming sewage and wastewater until it can be removed by pumping for transport to a separate sewage disposal or treatment facility.

So yes, a "closed vault septic system" is a closed-septic tank and thus a holding tank that has to be pumped out frequently.

In some texts and countries, people use the word "vault" as a more elegant-sounding synonym for "tank".

That's appropriate in that the general definition of "vault" is a large room or chamber used for storage, especially an underground one. But if you're storing sewage, not money, in an underground chamber that is water-tight and does not discharge any effluent out of the tank to a septic drainfield or other treatment system, then it's a closed septic vault or a septic tight tank.

Synonyms: all of these phrases refer to the same thing:

• "septic holding tank"
• "tight tank"
• "tight septic tank"
• "closed vault septic system"
• "closed vault septic"
• "closed vault septic tank"
  

Watch out: Holding tank septic systems (discussed above in detail on this page) or closed vault septic systems, are not permitted in most jursdictions for most situations, with a few exceptions such as a restaurant along the Hudson River.

The reason is that "closed vault septic system" is an oxymoron in that it includes the word "system" which implies that the sewage is being treated in some way. But a holding tank does nothing useful except to store sewage and other wastewater.

It does not and can not discharge treated effluent into the local environment.

A conventional septic tank

is also water tight and also receives sewage and wastewater from a building or buildings, but in a conventional septic tank, baffles keep solid waste in the tank while permitting clarified effluent to exit the septic tank to flow into a treatment system such as a septic drainfield or mound.

In the septic effluent treatment system, also called a soil absorption system or SAS, soil bacteria further digest pathogens in the wastwater sufficiently that it can then safely flow into surrounding soils or evaporate into air above the drainfield or mound.

We want to install a holding tank in Ohio for a modular cabin

Address is 5430 Gieringer Avenue Cleves Ohio a side road that dead ends off East Miami Rvr Road.? Want to put a Modular cabin or something on the site. Their is water on the property and electric would be easy hook up On 2021-04-07 by Joshua A Chapman SR

by (mod) - Septic tank holding systems are not code approved in most locations

@Joshua A Chapman SR,

Septic tank holding systems are not code approved in most countries and cities so before spending money on that topic you need to check with your local building or plumbing department.

The Cleves website is http://www.cleves.org/

where you will see that officials have done a fantastic job at making it (apparently impossible) to find out how to call, email, or even walk-in to anyone's office: I've had no success finding actual contact information.

Here's the Cleves Department of Planning and Zoning

5000 gallon holding tank pumped out and filled back up in two months - with rain water

Hello, 5000 gallon holding tank pumped out and filled back up in two months with rain water.

Don't see it leaking out anywhere, no wet spots, so only leaking in? Any idea where could it be leaking at? Thanks On 2021-02-19 by Pam -

by (mod) - causes for abnormally-fast fill-up of a closed vault or tight septic tank

@Pam,

Are you sure we're really discussing a septic holding tank? Those are not legal in most jurisdictions.

If it really is a holding tank, then there are two ways the tank may "fill-up"

- water is running in the building - someone might, for example, not have noticed a toilet that's running constantly

- water is leaking into the holding tank from outdoors: from roof runoff, surface runoff, or groundwater leaking into the tank;

If a careful inspection of the tank cover, lid, access ports, shows nothing suspicious, then a more-thorough inspection of the tank sides and bottom should be made when the tank is pumped out.

Watch out: do not try to enter a septic tank to "inspect" it - doing so can be quickly fatal. Special training, equipment, and assistance are needed.

For more-conventional septic tanks:

If "rainwater" is filling your septic tank it's also flooding your drainfield and your septic system cannot work.

You need to divert rainwater or surface runoff away from the septic system and be sure there are no leaks into the tank.

BUT

It's entirely possible thatwhta's actually happening is your septic drainfield is saturated and has failed and is draining backwards into the septic tank.

Finally:

It is normal for a septic tank, in regular use, to be full, all the time, except for a few days to a week right after it has been pumped.

...

Continue reading  at SEPTIC TANK PUMPING SCHEDULE or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see SEPTIC / SEWAGE HOLDING TANK FAQs - questions & answers posted originally on this page.

Or see these

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Questions & answers or comments about using a septic holding tank, applications, code approvals, maintenance.