Manifolding totes: four mistakes, four fixes
Connecting several containers into one tank is the most requested plumbing job we do and the one with the most reliable failure modes. All four are geometry, not hardware.
- Sheet
- 97
- Revision
- 2026-10
- Scale
- 1:1
- Drawn at
- Peoria IL
Totes connected low on the outlet side equalise and behave as one tank. Connected any other way, they behave as several tanks having an argument.
Connecting high instead of low
People tee into the top fittings because it is easier to reach. The containers then fill to the header and stop equalising, so the first tank in line does all the work. Connect at valve height, on the outlet side, every time.
Restricting the header
A 2-inch outlet reduced to a 3/4-inch header turns a bank into a trickle. Use full-bore fittings and keep the header at least as large as a single outlet. Flow through a 2-inch butterfly on water is 25–40 gpm; a header should not be the bottleneck.
No isolation valves
Without a valve per container you cannot take one out of the bank, which means you cannot service a weep, swap a unit or drain for winter without emptying everything. One ball valve per tote is the cheapest insurance in the build.
An unlevel header
A quarter of an inch of slope across three containers is enough to make the low one carry the load and the high one never fill. Level the pad, or level the stands, but do not level by eye on gravel.
The overflow nobody sizes
A bank needs one overflow, at the end of the run, sized for the full inflow. If you are filling from a 3-inch line and overflowing through a 1-inch bulkhead, the bank becomes a fountain in the first real event. Size the overflow at least as large as the inlet, screen it, and point it somewhere that is not the foundation of a building.
The build sheet we work from
- Header height
- Valve centreline, outlet side
- Header size
- 2 in minimum, matched to the largest outlet
- Isolation
- One full-port ball valve per container
- Fittings
- Full bore, bulkhead with EPDM both sides
- Overflow
- One per bank, at the end, sized to inlet, screened
- Sacrificial position
- First container in line takes the dirtiest inflow
- Pad
- Level within 1/8 in across the bank
- Weight to plan for
- 2,420 lb per filled 275 — concrete, not gravel
- Gravity beats a pump wherever the geometry allows. A pump is one more thing to fail on a Sunday.
- If you need pressure, put the pump after the header and before the use point, never between containers.
- Put the sacrificial container first and expect to clean it most often — it is doing the whole bank a favour.
- Label flow direction on the header. Six months later nobody remembers which end is which.
Four banks we have built
| Use | Containers | Base grade | Notes |
|---|---|---|---|
| Barn roof rainwater | 4 × 275 | Grade B | Gravity only, winter drain kit, opaque wrap |
| Brewery hot liquor backup | 3 × 330 | Food grade | Insulated, pumped return, cycle 3 washed |
| Nursery irrigation buffer | 6 × 275 | Grade C | Pumped, filtered, sacrificial first position |
| Municipal brine make-up | 8 × 330 | Grade B | Two banks of four, cross-tied, heat traced |
Sketch it on a napkin
Send a photo of the drawing with the inflow size and the use point height. You will get a parts list and a fixed price back — the geometry is the hard part and we have made the mistakes already.