A holding tank, also known as a retention tank, is a container used to temporarily store wastewater and sewage on properties that are not connected to sewer or septic systems. Holding tanks provide a means of collecting wastewater until it can be properly disposed of offsite. While holding tanks can be a viable wastewater solution in some cases, there are some notable downsides to consider before installing one on your property.
Page Contents
- 1 Upfront Costs
- 2 Frequent Pumping
- 3 Labor Intensive Maintenance
- 4 Storing Sewage on Site
- 5 Limitations on Water Use
- 6 Permitting Difficulties
- 7 Future Connection Requirements
- 8 Property Value Impacts
- 9 Environmental Setbacks
- 10 Commercial Limitations
- 11 Risk of Improper Installation
- 12 Reliance on Contracted Services
- 13 Limited Tank Life Span
- 14 Comparative Costs Over Time
- 15 Requirement for Eventual Replacement
- 16 Difficulties Finding Service Providers
- 17 Risk of Pump Failure
- 18 Freezing Climate Challenges
- 19 Lack of Redundancy
- 20 Restrictions on Water Treatment
- 21 Difficulty Finding Allowable Drain Sites
- 22 Requirement to Connect to Sewer
Upfront Costs
One of the biggest downsides of a holding tank system is the high upfront installation cost compared to other onsite systems. Installing a holding tank requires excavation equipment to bury the large tank, special transportation equipment to deliver the tank, and expert labor for proper installation and hookups. The tank itself can cost anywhere from $1,500 to over $5,000 depending on the size and material. Then factor in additional costs for building permits, site preparation, and hooking it up to your home’s plumbing. Overall, expect to spend $5,000-$15,000 or more for a complete holding tank installation. This high initial investment may not make financial sense for properties that could potentially connect to sewer lines down the road.
Frequent Pumping
Since holding tanks have limited storage capacity, they need to be pumped out frequently to avoid overflows. The pumping frequency depends on the tank size and household wastewater usage, but tanks typically need pumping every 1-2 weeks. Each pumping service can cost $200-$500, so this equates to thousands of dollars in annual pumping costs. The frequent pumping schedule also means dealing with regular service disruptions when trucks come to pump out the tank. If pumping schedules are not diligently maintained, there is a high risk of the tank overflowing raw sewage onto the property.
Labor Intensive Maintenance
Beyond just the pumping costs, holding tanks have high ongoing maintenance requirements. Homeowners must vigilantly track wastewater levels and arrange pump outs before the tank reaches capacity. Skipping just one needed pump out can lead to costly overflows or damage. Some local regulations require submitting periodic pumping logs or inspection reports as well. Overall, holding tanks involve a substantial labor burden to coordinate proper maintenance year after year.
Storing Sewage on Site
One major downside is that holding tanks require you to store raw sewage on your property until it can be pumped out. This differs from septic systems that treat and disperse wastewater onsite. Storing concentrated waste raises sanitary concerns and can also lead to foul odors around the tank. Any leaks or cracks in the tank would release sewage below ground on your property. Tank overflows that send raw sewage above ground pose even greater health hazards.
Limitations on Water Use
Since holding tanks have finite storage capacity, households must restrict their wastewater volumes to avoid overfilling the tank. This means limiting activities like long showers, running dishwashers or washing machines, and flushing toilets frequently. Water conservation is positive, but these limitations on household water use can be challenging. Large gatherings, busy weekends, or other high-use events can overwhelm a holding tank’s capacity as well.
Permitting Difficulties
Getting permits approved for holding tanks can be more difficult than other onsite wastewater systems. Many local regulations strictly limit the allowable situations where holding tanks may be installed. For example, they may only approve holding tanks as temporary systems while a permanent septic system is being repaired. In some areas, holding tanks are banned altogether for new construction. If local authorities deny a holding tank permit, it necessitates costlier sewer or septic connections.
Future Connection Requirements
Some municipalities approve holding tank permits on the condition that the property must connect to sewer lines if they become available in the future. When sewer access arrives, homeowners must bear the cost to decommission the holding tank, install new plumbing, and pay ongoing sewer fees. So there is a risk that the holding tank ends up being an intermediate system that requires a future upgrade.
Property Value Impacts
Since holding tanks have high maintenance demands and strict usage limits, they are generally viewed less favorably than a septic system. Limitations from the holding tank may turn away potential buyers if you ever want to sell the home. Disclosing pumping schedules and costs may deter buyers as well. This could make a home with a holding tank more difficult to sell or reduce the sale price compared to septic-connected homes.
Environmental Setbacks
While holding tanks contain wastewater until it gets pumped out, environmental agencies still view them as less favorable than septic systems or sewer connections. Holding tank wastewater ultimately gets disposed of at sewage treatment plants that have broader environmental impacts. And any overflows or leaks from holding tanks seepage can contaminate groundwater and soils. For these reasons, environmental agencies aim to minimize holding tank use compared to other options.
Commercial Limitations
For restaurants, office buildings, hotels and other commercial properties, holding tanks are generally not a feasible long-term solution. Holding tanks have far too small of capacity and need for frequent pumping to support the high wastewater volumes from most businesses. In some areas, there are strict limits on how holding tanks can be used for commercial buildings. The high ongoing costs and logistical challenges make holding tanks unsuitable for all but the smallest commercial uses.
Risk of Improper Installation
Since holding tanks have large storage capacity, proper installation is crucial to avoid environmental contamination. However, some contractors may cut corners and install tanks with inadequate preparations or insufficient pumping access. If a holding tank hasn’t been sized and installed correctly, it increases the risks of groundwater pollution through leaks or cracked tanks. This underscores the importance of hiring qualified, licensed contractors for the holding tank installation.
Reliance on Contracted Services
With a holding tank, homeowners are fully reliant on pumping contractors to regularly service the tank. If there are no available or willing contractors in your area, it could become extremely difficult to maintain the holding tank on your schedule. Issues like pump contractor shortages, labor strikes, or extended bad weather could make it impossible to pump out the tanks on time. This reliance on contracted pumping services creates a risk that holding tank owners can’t directly control.
Limited Tank Life Span
Even with proper maintenance, holding tanks have a finite lifespan before needing replacement. Some degrade faster depending on tank material and environmental conditions. But generally after around 20-30 years, corrosion and small leaks make replacement necessary. This adds another major expense to factor in down the road beyond just the annual pumping costs.
Comparative Costs Over Time
While the upfront cost of a holding tank may seem less than a full septic system, the ongoing costs tip the scales in the other direction. When accounting for regular pumping, occasional repairs, the need for eventual replacement, and decommissioning when sewer arrives, the lifetime costs of a holding tank usually exceed alternative wastewater systems. These recurring expenses amortized over decades make holding tanks an expensive long-term option.
Table comparing holding tank costs to septic system costs over 20 years
| Cost Factor | Holding Tank | Septic System |
|---|---|---|
| Initial investment | $10,000 | $20,000 |
| Scheduled pumping | $15,000 | $3,000 |
| Unscheduled pumping | $4,000 | $1,000 |
| Repairs | $3,000 | $2,000 |
| Replacement | $12,000 | $10,000 |
| Total 20-year cost | $44,000 | $36,000 |
Requirement for Eventual Replacement
Holding tanks are designed to be “temporary,” so after some years they require replacement with a new tank or sewer connection. Old holding tanks become inefficient as they accumulate sludge, corrode, and develop leaks over time. Most authorities require properly abandoning old holding tanks and installing brand new ones if owners wish to keep the temporary holding tank system. Replacement holding tank costs can be comparable to installing a whole new septic system.
Difficulties Finding Service Providers
The need for frequent pumping makes finding reliable pumping service essential for holding tank owners. But not all septic companies are willing to take on scheduled pumping contracts due to the hassle and low profit margins. Some rural areas have few septic contractors to choose from, period. This can make finding pump out services difficult, leading to missed pumpings and overload risks.
Risk of Pump Failure
Some holding tanks rely on pumps to move wastewater into the tank or to control dosing out to a drain field. Pump malfunctions can make the tank unusable until repairs are completed. Failed effluent pumps leading out to the drain field means wastewater can back up into the home. Pump issues add one more failure point to be aware of.
Freezing Climate Challenges
In areas where winters drop below freezing, holding tanks can become compromised by frozen contents or frost heave pushing the tank upwards. Wastewater freezing in the inlet and outlet pipes can also prevent proper function until it thaws. These winter-related risks require extra insulation, heat tapes, or other accommodations.
Lack of Redundancy
Unlike septic systems that have multiple components and a drain field, holding tanks offer no redundancy if something goes wrong. Since all the wastewater goes to a single tank, any issues with that tank compromise the whole system. There is no backup tank or failsafe if the solitary holding tank is overfull, damaged, or otherwise compromised.
Restrictions on Water Treatment
Certain water treatment systems like water softeners and iron filters send additional wastewater volume to the holding tank. To avoid overfilling issues, many holding tank owners are advised to avoid installing any water treatment systems. This leaves owners stuck with hard water, iron staining, and other water problems.
Difficulty Finding Allowable Drain Sites
Owners wishing to add a drain field from a holding tank to convert it to a septic system may struggle to find a suitable location. The drain field area must meet various setback limits from surface waters, wells, foundations, and property lines. This makes finding an acceptable drain field site challenging on some properties.
Requirement to Connect to Sewer
If municipal sewer lines become available, many authorities require holding tank owners to connect within a timeframe like 90 days. Sewer connections add substantial cost for decommissioning the tank, installing new plumbing, paying permit fees, and covering sewer assessments. Being forced to connect to sewer nullifies the supposed cost savings from installing a holding tank.
Conclusion
Holding tanks provide temporary wastewater storage in scenarios without access to sewer service or suitable drain field locations for septic systems. However, the logistical headaches and high costs associated with maintaining holding tanks over the long term lead to notable downsides in most cases. Frequent pumping schedules, usage limits, aesthetic issues, environmental risks, and eventual replacement requirements turn many homeowners off from holding tanks. Carefully weighing the long-term costs and responsibilities can help determine if a holding tank or alternative wastewater system makes more sense for your situation. But in general, holding tanks are best suited as a short term solution.