Installation Information Concrete
Concrete Septic Tank – INSTALLATION GUIDELINES
Proper installation of each tank is absolutely critical for it to function properly and remain watertight. Many of the
problems experienced with tank operation, or of tanks leaking (either water flow into or out of the tank), or of
premature system failure can be attributed to incorrect procedures during installation. Improper installation
practices can seriously damage the tank or other system components, can reduce the capacity or efficiency of the
tank, and can even cause serious personal injury.
This INSTALLATION GUIDELINE is offered to assist the installer with advance planning, proper site preparation,
safe handling and sound installation procedures. It should also prove helpful to designers, inspectors, and
homeowners. It is one of the essentials for long lived systems.
PLAN YOUR PROJECT…. You will need to know the measurement from the underside of the tank to the bottom
of the tank’s inlet opening in order to prepare the sub-bed elevation to allow the tank to properly receive the sewer
pipe coming from the building. Review the manufacturer’s most current literature and drawings, or call them for
these critical dimensions.
Keep in mind that the site where the tank is to go must be accessible by large and heavily loaded trucks
(sometimes up to 50,000 pounds). This site must allow for reasonable access under the trucks own power (not be
towed or pushed); it must be clear of trees and branches, overhead wires, underground utilities or other structures
that could be damaged by or interfere with the delivery and off loading of the septic tank. Typically, the delivery
truck must be able to safely get to within three feet of the excavation and be on stable and level ground in order to
unload and set the tank.
The purchaser is responsible for any damage to the site, the delivery truck or the tank once the truck leaves the
pubic thoroughfare and enters the work site. Therefore, adequate access for delivery equipment to get to the
excavation and unload the tank is important.
Standard concrete septic tanks are not designed to be installed under traffic loads or to carry unusual heavy
construction or maintenance equipment. (Tanks designed for traffic loadings or special situations are available by
For the safety of your backhoe operator, and the public good, all buried utilities should be identified and located
before you dig. Here is a recommended procedure:
Call before you dig to arrange for Manitoba Hydro to check and mark your property for electrical and/or natural
gas lines. The service is free to locate Manitoba Hydro-owned underground facilities.
Call 1-888-MBHYDRO (1-888-624-9376) or in Winnipeg call 480-1212. Remember to also call any other utility or
service companies which may be providing service to that location.
Please note that you must CALL. We cannot accept email requests for appointments.
From April 1 to October 31, please call at least one week ahead to book an appointment. From November 1 to
March 31, we require at least two business days notice.
One call can prevent service outages, equipment damage, costly repairs, environmental pollution, personal injury,
and even death.
Be prepared to provide them with the project address, how to reach you, and anything else necessary or unique
about the location.
They will either send someone to mark their underground lines, or advise that their underground services are
unaffected by your proposed excavation.
Do not begin digging until you have been contacted by each utility or service. Lay out your hole a minimum of 10
inches and no more then 20 inches larger than the tank, to allow space to properly compact the fill material. For
worker safety, it is recommended that no worker should be in the excavation until the tank has been set.
Proper bedding is important to ensure a long service life of an onsite septic system, and to allow the tank to be set
level. A sand or pea gravel layer, a minimum of 5 inches thick, overlying a firm and uniform base is
recommended. Correct compaction of the underlying soil and sand/gravel bed is critical to insure the tank
is set level and stays that way. Tanks must not bear on large stones, boulders, or rock edges.
First, inspect the delivered tank while it is on the truck; check for any defects or shipping damage, and note that it
is the tank ordered. If there are any discrepancies, point them out to the driver, and clearly note them on both the
driver’s bill of lading and your delivery documents.
Prior to placement, the tank’s orientation should be confirmed (inlet openings should face the residence). After
placement, check that the tank is level, and that the inlet elevation will closely match the bottom of the pipe
coming from the house at the point where it will enter the tank. Be sure that the pitch of the sewer pipe from the
house to the tank meets the local Code requirements.
Setting of the tank should be done by the tank manufacturer’s truck driver. This will insure that it is handled
properly, with appropriate special equipment, as may be needed.
TANK LOADING & UNLOADING
- Operator is to inspect the, crane, wire rope, chain hooks, lift bar and straps for any damage or excessive
ware before loading or unloading any tank.
- The operator (D&L Concrete & Fiberglass Products Ltd. trained employee) is the only person permitted
to operate the delivery truck or it’s crane.
- The operator is to ensure that no one is standing directly behind the tank or in an area they deem unsafe
when being loaded or unloaded.
- No person(s) shall aid in guiding the tank until it is clear of the deck and they have been given the “Okay”
from the operator to do so. When assisting in guiding the tank the operator will provide an aid and no
person(s) shall be closer than 1m from the edge of the excavation.
- When the tank is being lower into place it is only to be guided from the side that is visible to the operator.
Once the tank is within 6” of resting on the bottom of the excavation, the operator will allow a person(s) to
guide the tank from the front to line up the plumbing.
- All spectators MUST be a minimum of 10m from the delivery truck while installing the tank.
Use only high quality seals for all joints. Mating surfaces must be clean; at a minimum, sweep off any debris
before placing the sealant. Recheck tank for joint alignment and grade before backfilling.
With time, pipes may settle, and this changed angle of pipe entry/exit will begin to leak unless it is fitted with a
flexible joint connector.
Care should be taken when back filling, to prevent damage or misalignment to the entry and exit piping, the tank
and fittings, or any joints. Backfill should be placed in uniform, mechanically compacted layers less than 24 inches
thick. Do not backfill and compact one or two sides before backfilling the other sides. Excavated material may be
reused for this purpose, but may not contain any large stones.
Concrete tank walls are significantly heavier than fiberglass or high-density polyethylene tanks, and are least
likely to float in a flooded excavation. However, even empty concrete tanks will float if the water level rises high
enough. Therefore, to prevent this from happening after the tank is set, keep water pumped out of the excavation
until backfilling is completed, or fill the tank with water, or place soil on top of the tank.