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IBC connectors do not come in just one standard size. The most common outlet is S60x6, often called a 2-inch IBC connection, DN50, or 60 mm coarse thread. But some totes use 2-inch BSP, NPS, or NPT threads, while others use larger coarse threads such as S75x6 or S100x8. These connections can look similar without actually fitting each other.
The safest approach is to identify both the outside thread diameter and the thread pitch before buying an adapter.
Common IBC Connector Sizes
The table below covers many of the connections you may find on the discharge valve of an IBC tote.
| Connector | Approximate outside diameter | Thread pitch | Where you may see it |
|---|---|---|---|
| S60x6 | 60 mm | 6 mm | Most common IBC outlet |
| 2-inch BSP | About 59.6 mm | About 2.3 mm | Fine-thread outlets and adapters |
| 2-inch NPS | About 60.3 mm | About 2.2 mm | Some North American fittings |
| 2-inch NPT | Around 60 mm | Fine tapered thread | Plumbing adapters and some outlets |
| S75x6 | 75 mm | 6 mm | Some IBC valve connections |
| M80x3 | 80 mm | 3 mm | Less common valve connection |
| S92x4 | About 88–92 mm | 4 mm | Larger DN80-style connections |
| S100x8 | Around 90–100 mm depending on where measured | 8 mm | Larger IBC valve connections |
S60x6 is the connection most people encounter when adapting an IBC tote for rainwater storage. The "60" refers to an outside thread diameter of about 60 mm, while the "6" refers to the distance between thread peaks.
The important point is that "2 inch" does not identify the thread by itself. Several connections with roughly the same diameter use very different thread shapes and pitches.
What Is an S60x6 IBC Connector?
S60x6 is a coarse buttress-style thread commonly used on IBC discharge valves.
Its basic dimensions are:
- About 60 mm outside diameter
- About 6 mm thread pitch
- Often associated with DN50
- Commonly described by sellers as a 2-inch coarse IBC thread
It is the most common starting point for adapters used with garden hoses, irrigation pipe, pumps, valves, and other rainwater equipment.
However, calling S60x6 simply "2-inch thread" can cause problems. It is not the same thing as a standard 2-inch plumbing thread.
Why DN50 and 2 Inches Can Be Confusing
You may see the same IBC fitting described using terms such as:
- S60x6
- DN50
- 2-inch IBC
- 60 mm coarse
- Buttress thread
These descriptions do not always mean exactly the same thing.
DN50 is a nominal size. Nominal means it describes the general size class rather than the exact outside diameter of the threads.
That is why a fitting called "2 inch" can have an outside thread diameter close to 60 mm rather than exactly 2 inches.
Always give the actual thread standard more weight than the nominal pipe size.
For example, S60x6 and 2-inch BSP can both measure close to 60 mm across the threads, but their thread pitches are very different. S60x6 has widely spaced coarse threads, while BSP has much finer threads.
S60x6 vs 2-Inch BSP
These are easy to confuse because their outside diameters are similar.
An S60x6 connection is roughly:
- 60 mm diameter
- 6 mm between thread peaks
- Very coarse thread
A 2-inch BSP connection is roughly:
- 59.6 mm diameter
- About 2.3 mm between thread peaks
- Fine thread
If you place the fittings next to each other, the difference in thread spacing is usually obvious.
Do not force one onto the other. It can damage the threads and may create a connection that leaks.
S60x6 vs 2-Inch NPT or NPS
NPT and NPS are common pipe-thread terms in North America.
NPT, or National Pipe Taper, uses a tapered thread. The fitting becomes tighter as it screws together.
NPS, or National Pipe Straight, uses a parallel thread.
An S60x6 IBC outlet is different from both. Its large, widely spaced buttress threads are designed differently from ordinary pipe threads.
A typical setup therefore looks like:
IBC valve → S60x6 adapter → NPT, BSP, hose barb, camlock, or garden-hose connection
The adapter provides the change from the IBC-specific connection to whatever plumbing system you want to use.
Larger IBC Connector Sizes
Not every IBC uses the common S60x6 outlet.
S75x6
S75x6 has an outside thread diameter of about 75 mm and a 6 mm pitch.
It appears on some valve and container combinations and is noticeably larger than S60x6.
An S60x6 adapter will not fit it.
M80x3
M80x3 has an outside diameter of about 80 mm and a much finer 3 mm pitch.
The diameter alone is not enough to identify it because several IBC connections fall into a similar size range.
S92x4
S92x4 is a larger connection with an outside diameter generally around 88 to 92 mm and a 4 mm pitch. It is associated with some larger-flow IBC valves.
S100x8
S100x8 is another large coarse IBC thread. Its 8 mm pitch is considerably wider than ordinary pipe threads and is commonly associated with larger outlets.
These larger fittings are less common on ordinary rainwater totes, but they matter when buying used IBCs because replacement adapters may not be as readily interchangeable.
Camlock Connectors Are Different
Some IBC valves end in a camlock, also called a cam-and-groove connection.
A camlock is a quick-connect system rather than an ordinary screw thread. Two arms on the female coupling lock around the matching male fitting.
A 2-inch camlock is common on equipment used for transferring liquids.
Do not assume that a tote with a 2-inch camlock also has an exposed S60x6 thread underneath it. The valve configuration varies. Some assemblies combine camlock fittings with another threaded connection.
Identify the connection that you will actually attach your hose or adapter to.
Garden-Hose Connections Are Usually Added With an Adapter
A standard IBC valve usually does not connect directly to an ordinary garden hose.
For a rainwater setup, you may use an adapter such as:
S60x6 female → garden-hose thread
or:
S60x6 female → pipe thread → valve → hose fitting
The first option is simple for filling watering cans or running a short gravity-fed garden hose.
The second gives you more flexibility if the system includes irrigation pipe, a pump, filter housing, or additional shutoff valves.
Remember that the connector size does not determine water pressure. An elevated IBC can provide gravity flow, but pressure depends mainly on the vertical height of the water above the outlet.
How to Measure an IBC Connector
Measuring the connection is safer than ordering an adapter based only on the tote brand.
1. Measure the outside diameter
Account for selecting the right thread is used for ibc tote valves to compare long-term maintenance priorities for the installation.
Measure straight across the outside edges of the male threads.
Calipers make this easier, but a ruler can provide a useful first check.
For example, a measurement close to 60 mm puts S60x6, 2-inch BSP, and some 2-inch North American pipe threads into consideration.
Diameter alone is therefore not enough.
2. Measure the thread pitch
Measure from the peak of one thread to the peak of the next.
A typical S60x6 connection has about 6 mm between thread peaks.
A fine 2-inch BSP connection has spacing closer to 2.3 mm.
This difference is often the easiest way to separate a coarse IBC thread from a fine pipe thread.
3. Check whether the thread is coarse or fine
A coarse S60x6 outlet usually has only a few large threads visible.
BSP, NPS, and NPT connections have many more thread peaks over the same distance.
4. Check the connection type
Look for whether the outlet is:
- A male threaded stub
- A female thread
- A camlock
- Part of an integrated valve
- An adapter already fitted to the original valve
Used totes sometimes arrive with an adapter still installed. You may therefore be measuring the adapter rather than the original IBC outlet.
Do Not Identify the Fitting by Tote Capacity
A 275-gallon IBC and a 330-gallon IBC do not automatically use different connector sizes.
Container capacity does not reliably identify the valve thread.
Two totes with the same capacity can have different valves depending on the manufacturer, bottle design, previous contents, region, and replacement parts.
Measure the actual fitting.
Do Not Identify It by Manufacturer Alone
Knowing the manufacturer can help narrow the possibilities, but it should not replace measurement.
IBC manufacturers have produced different valve designs over time. A used tote may also have had its original valve replaced.
Measure:
- Outside thread diameter
- Thread pitch
- Connection style
Then choose the adapter.
Choosing an Adapter for a Rainwater System
Once you know the IBC-side thread, determine what connection you need on the other side.
Common choices include:
- Garden-hose thread
- Hose barb
- BSP pipe thread
- NPT pipe thread
- PVC or polyethylene pipe connection
- Camlock fitting
- Ball valve
Think about the entire path before buying the adapter.
For example:
IBC tote → outlet valve → adapter → shutoff valve → irrigation line
Or:
IBC tote → adapter → pump suction line → pump → filter → garden line
Every connection needs to match the next component.
A large IBC outlet followed by a very small hose can also restrict flow. If you need higher flow for irrigation or pumping, consider the diameter of the whole water path rather than just the tote outlet.
Check the Gasket as Well as the Thread
Many IBC adapters seal using a flat gasket rather than relying entirely on the threads.
That gasket matters.
A fitting can have the correct thread and still leak if:
- The gasket is missing
- The gasket is damaged
- The sealing surface is dirty
- The adapter is cross-threaded
- The fitting is overtightened
- The gasket material is unsuitable for what was previously stored in the tote
For rainwater use, inspect used valves and adapters carefully before putting the tote into service.
If you do not know what the IBC previously contained, do not assume that rinsing it makes the container suitable for household water or food-growing uses.
What Size Should You Choose for a Rainwater IBC?
If your tote has the common S60x6 outlet, choosing an S60x6 adapter gives you a convenient way to transition to standard garden or plumbing fittings.
The size on the other side depends on the job.
A garden hose may only need a hose-thread adapter. A larger gravity irrigation line may benefit from maintaining a larger pipe diameter. A pump connection should be sized according to the pump's inlet requirements, expected flow, suction conditions, and plumbing layout.
Do not reduce the line simply because a smaller adapter is easier to find.
Frequently Asked Questions
What is the most common IBC connector size?
S60x6 is one of the most common IBC discharge-valve connections. It has an outside thread diameter of about 60 mm and a coarse 6 mm pitch.
Is an S60x6 fitting the same as a 2-inch pipe fitting?
No. S60x6 is often called a 2-inch IBC fitting, but it is not the same thread as 2-inch BSP, NPT, or NPS. You normally need an adapter to connect it to standard plumbing.
How can I tell whether my IBC has S60x6 or BSP threads?
Measure the thread pitch. S60x6 has widely spaced threads about 6 mm apart. A 2-inch BSP thread has much finer spacing of roughly 2.3 mm.
Are all 275-gallon IBC tote fittings the same size?
No. Tote capacity does not guarantee a particular outlet thread. Measure the actual valve connection before ordering an adapter.
Are 275-gallon and 330-gallon IBC connectors interchangeable?
Sometimes, but not automatically. Both capacities can use common fittings such as S60x6, while other valve types also exist. The thread diameter and pitch need to match.
Can I connect a garden hose directly to an IBC tote?
Usually you need an adapter. A common arrangement converts the tote's IBC thread to garden-hose thread. You can then attach a hose, valve, or irrigation line.
What does DN50 mean on an IBC fitting?
DN50 is a nominal size designation associated with fittings in roughly the 2-inch size range. It does not mean the outside thread measures exactly 50 mm. Always check the actual thread standard before choosing an adapter.
Why does my 2-inch IBC adapter not fit?
"2 inch" can describe several different connections. Your tote might have S60x6, BSP, NPT, NPS, a camlock fitting, or another IBC-specific thread. Measure both the outside diameter and thread pitch rather than relying on the 2-inch label alone.
