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Our 1250 gallon septic tank is an ideal home tank size for a conventional four-bedroom residence. For area home owners, it is the most common choice of concrete tank sizes in New Hampshire.

1250 Gallon Septic Tank

Water and waste water up to 1250 gallons can be held by this septic tank. Plumbers and home owners appreciate that our tanks meet all best-practice requirements of ASTM C 1227 & NPCA.

Plumbing pipes and drains that service a home can be run to either side of this mid-seam septic tank or the center inlets. The same drains option is also available on the outlet of the tank, extending out to the leach field from its side or middle outlet drainage pipe. Outlet pipes entering and leaving the precast structure gain a flexible, watertight seal connection with Polylok IV closed-end boots used for the tank's penetrations. Plumbers and plumbing services teams appreciate the installation versatility our tanks provide. For septic services job maintenance and installation, AJFoss' septic tanks save time and money.

Ask our team of experienced area septic professionals at A.J. Foss about the wide variety of sizes and designs of one and two-compartment septic tanks and accessories we manufacture in our state of art facility.

3 Bedroom Building Septic Tank Installation

1250 gallon septic tank installed for 3 bedroom home in NH during winter.

1250 Gallon Septic Tank Details
Tank dimensions	8’ Long 5’8” wide 6’ Tall
Number of bedrooms supported	Up to 4 - Minimum size now required
Pre-assembled	Yes
Ideal for high water table	No but our 1500 gallon monolithic septic tank is.
Average retail cost	$1250
Number of tank lids (covers)	2
Can come in traffic rated (H20) capacity	Yes
Concrete strength	5,000 PSI
What are its gallons per vertical inch	23
Weight	11,500 lbs.
Fiber reinforced	Yes
Number of inlets boots (Up to schedule 40 pipe can slide through)	3
Height of inlet from bottom of tank to bottom of pipe	63”
Number of outlets boots (Up to schedule 40 pipe can slide through)	3
Height of outlet from bottom of tank to bottom of pipe	60”
Required height of inlet baffle (20% of liquid level)	12”
Required height of outlet baffle (40% of liquid level)	23”

Brand-new AJFoss 1250 gallon precast concrete septic tank with plastic risers for water-tight seal.

Frequently Asked Questions

What are the most common types of systems in our area for wastewater management?

- Conventional systems such as Concrete Chamber Systems (for anaerobic systems)
- Mound Septic Systems (an above-ground septic system with a drain field mound)
- Sand Mound or Sand Filter Septic System
- Gravity Septic System (requires a gentle slope)

What is the average cost of a 1250 gallon precast concrete septic tank?

Answer: Regarding septic tank costs, the retail average job cost for a 1,250 gallon system is $1250. The main factor that affects the average price of residential septic tanks include: House size and water use per day (or consistent flow of wastewater) which affects the gallons capacity of water flow based on water usage. For example, area five or 6-bedroom homes will require at least a 1,500 gallon tank or larger tanks, while a two-bedroom house or three-bedroom house will require a smaller tank; thus, lower tank prices.

What affects the average price of septic system installation by professional installers?

Service and job factors that can affect the average price of septic tank installation costs include:

- Type of septic tank (Precast concrete versus lighter fiberglass tanks)
- Size of drainage field or absorption field (which can affect labor costs)
- Existence of nearby water sources (which can require converting septic system designs from conventional septic systems to alternative systems. This includes aerobic systems that use aerobic bacteria such as Norweco Singlair Wastewater Treatment Systems.

Additional cost of installation factors include soil testing to determine soil conditions.

Engage with qualified professionals to obtain accurate cost estimates for your specific tank cost.

What is the most common septic tank size?

Answer: In New Hampshire it is the 1250 gallon septic tank. It is the most common tank specified and used by septic designers. It is the smallest tank allowed by the NH DES and it is used for up to a four bedroom house. For additional bedrooms you would add 250 gallons per bedroom. So a 5 bedroom house would require a 1500 gallon septic tank.

Can you drive over a 1250 gallon size septic tank?

Answer: A tank's design rating determines whether you can drive vehicles or heavy machinery over it. A.J. Foss manufactures 3 variations for septic installations: H-10 is for pedestrian traffic with 300 lbs. of live load per square foot plus 3' of burial depth. HD is for burial depth up to 5'. H-20 rating is for vehicular drive-over traffic & up to 6' of burial depth.

Is it ideal for high water table areas?

Answer: Our standard 1,250-gallon septic tank is manufactured in two pieces, with the seam at the middle. For a high water table area near a body of water, our 1250 gallon monolithic septic tank is ideal as the seam is at the very top of the septic tank. The liquid is below the lid so nothing can leak in or out.

How much does a 1250 gallon concrete septic tank weigh?

Answer: Our 1,250 gallon concrete septic tanks weigh approximately 11,500 lbs. Weights vary slightly among precast manufacturers depending on the dimensions, wall thickness, floor & top thickness and rebar reinforcement.

How many bedrooms does a 1250 gallon septic tank support?

Answer: In New Hampshire, a 1250 gallon tank supports up to a four bedroom home. It is the smallest tank size that can be specified on new designs for a 3-4 bedroom home since the rules were revised in 2012.

- 1250 gallon septic tank is used in up to 4 bedroom systems
- Most common tank size used in NH
- Smallest tank we recommend to use as a septic tank
- Is delivered pre-assembled for ease of installation

Why are steel tanks or plastic tanks generally not recommended?

Precast concrete remains the most common material for septic systems because it is robust, practical and long-lasting. Although they may seem at first to be an alternative to concrete, lighter-material plastic tanks and fiberglass tanks can undergo damage during installation. Structural damage to a plastic or fiberglass septic tank can require replacement of the entire tank. The only plastic septic tanks that A.J. Foss recommends are those used for alternative septic systems such as Norweco Singulair aerobic septic systems, which use oxygen-loving bacteria and an aerator to break down solid waste and create cleaner wastewater effluent for discharge to a drain field.

Features/Details*

1250 gallon septic tank is used in up to 4 bedroom systems.
Most common tank size used in NH.
Smallest tank we recommend to use as a septic tank
Is delivered pre-assembled for ease of installation

* Details shown are NH-specific; for details of other states’ specifications please contact us.

You may also be interested in these popular precast concrete septic tanks.

About the Author:

My father started the Andrew J. Foss, Inc. precast concrete company in 1963 at the age of 19. My precast education started at a very young age. He taught me everything I know about creating quality precast concrete products, from septic tanks to concrete headwalls. He also taught me to succeed in business you need to offer an exceptional product and treat your customers as you would expect to be treated. Now, as an owner of the company along with my brother Matthew, we've taken everything we've learned from our father to start the next generation of our family-owned precast concrete company.

1250 Gallon Septic Tanks: Precast Concrete