
Description
Fit your chosen tap
A 1-inch BSP tank adapter that combines a male mounting thread with a female socket for a separate tap or connector.
The compact black plastic body comes with one back nut and two red mounting washers.
Match the tank mounting and outlet fitting before assembly. Tap, tank and hose are sold separately.


A socket for a matching male fitting
The close-up shows the female thread inside the socket. It accepts a separate 1-inch BSP male fitting, such as a suitable tap or valve. The male thread on the other end is also 1-inch BSP.
The red washers are mounting seals for the tank wall. For a through-wall installation, separate them so one seats against each side of the wall before tightening the retaining nut.
Check the outlet fitting’s own sealing arrangement as well. The wall washers do not replace whatever seal is needed at the threaded tap connection.
Two ways to plan the mounting
Start with the outlet on your tank, then choose the arrangement that suits it.
Existing female thread
The male end can engage a matching 1-inch BSP female outlet. Check thread compatibility and a suitable sealing face; the through-wall nut-and-washer arrangement is not automatically needed or appropriate for every threaded outlet.
New wall opening
Check the wall thickness and surface against the actual fitting before preparing a hole. Remove the back nut and one washer, pass the body through the opening, then refit the washer and nut inside. Keep a mounting washer on each side of the wall.
Complete the outlet
Support the body while tightening and avoid distorting the plastic or tank wall. Fit the matching tap or connector with an appropriate seal, then check both the mounting and threaded joint for leaks before leaving water stored.
Questions about the one-inch adapter
Is this a reducing adapter?
No. The external male thread and the internal female socket are both 1-inch BSP. It provides a male-to-female connection without changing the nominal thread size. Check any separate tap or fitting is also the correct BSP size.
Where do the two red washers fit?
For a suitable through-wall installation, one washer sits outside against the connector flange and the other goes inside before the back nut. They seal the tank wall; they are not a pair of washers intended to sit inside the female socket.
Can I connect a one-inch BSP male tap?
Yes, the female socket accepts a matching 1-inch BSP male fitting. Check the tap’s sealing arrangement and that its handle and outlet have room to operate. The tap is separate from the adapter set.
What hole size does the tank need?
Check the actual adapter body, wall thickness and mounting surfaces before making an opening. The nominal 1-inch BSP designation identifies the thread and should not be used as a drill measurement. You also need access inside for the washer and back nut.
Product information & technical details
| SKU | BUTT1BSPM-F001 |
|---|---|
| Product type | |
| BSP thread size | 1" |
| Thread gender | Male, Female |
| Colour | Black |
| Material | Plastic |
| External connection | 1-inch BSP male |
|---|---|
| Socket connection | 1-inch BSP female |
| Back nut | 1 included |
| Mounting washers | 2 red washers included |
| Supplied contents | 1 adapter, 1 back nut and 2 washers |
What is BSP?
What is BSP thread size?
BSP (British Standard Pipe) is a nominal pipe-thread size, not a direct measurement of a fitting’s bore or outside diameter. For example, a ½-inch BSP male thread measures about 21mm across its outer thread crests.
These figures are approximate outside diameters of male BSP threads, to help identify the nominal size. They are not inch-to-millimetre unit conversions:
- 3/8" BSP → 16.66 mm
- 1/2" BSP → 20.95 mm
- 3/4" BSP → 26.44 mm
- 1" BSP → 33.25 mm
- 1.25" BSP → 41.91 mm
- 1.5" BSP → 47.80 mm
- 2" BSP → 59.61 mm
- 3" BSP → 87.88 mm
- 4" BSP → 113.03 mm
All our BSP threads are parallel (BSPP, to ISO 228), not tapered.
Measure across the outside of a male thread, then check its pitch and whether it is parallel or tapered. Diameter alone does not confirm compatibility. Check the product’s stated thread specification before connecting.
All delivery times are estimates and not guaranteed. Orders placed before 1 pm, Monday to Friday (excluding bank holidays), will be dispatched the same day, while orders placed after 1 pm will be dispatched by the end of the next working day.
If an invalid postcode or address is provided, the order will be cancelled without further notice, as we are unable to modify addresses or print labels for invalid postcodes.
Our standard delivery option is Royal Mail Tracked 48, which typically takes 3–5 business days. If you need your order more quickly, Expedited delivery via Royal Mail Tracked 24 is available, offering a 1–2 business day service.
Large or bulky items may be sent via courier at our discretion and are usually dispatched for next-day delivery. Please note that we only ship to mainland UK addresses; delivery to non-mainland locations, including the Highlands & Islands, may not be available for large or heavy items. If your address falls into one of these areas and you wish to purchase such items, please contact us with your postcode and order details before placing your order. If we cannot ship to you, you are welcome to arrange your own courier for collection.
All products, unless otherwise stated, come with a standard manufacturer warranty against faulty workmanship.
If your product fails within six months of delivery, please contact us with your order reference number, a description of the issue, and clear images illustrating the fault.
Should your item require a return for further investigation, it is your responsibility to arrange and cover postage back to us.
If we are unable to repair the fault, we may offer either a replacement or a full refund.
In cases where the item is inspected and found not to be faulty, or where damage is determined not to be due to manufacturing defects, you will not be entitled to a refund or replacement. We will then either return the item to you via standard post or dispose of it at your request.
You may return any order within 14 days of delivery. As soon as you receive your items, please inspect them carefully, taking reasonable care to keep both the product and its packaging clean and undamaged. If you discover an error or defect after 14 days, we reserve the right to decline your return. If your product fails or breaks after this 14-day time window then your order may be eligible for a warranty claim, please see our warranty information for more details.
To initiate a return, please contact us via our contact form to obtain a return authorisation and the correct returns address (different from the address on your invoice). This can also be done through your 'recent orders' page on your account if you are registered with Shop. Returns sent without prior authorisation will be discarded.
Returned items must be in the same condition in which you received them: unworn or unused, with tags attached and in their original packaging. You must include either a copy of your invoice or a slip with your order reference number inside the parcel. Please be sure not to obscure your return reference number on the label.
If you refuse delivery or reject the parcel without prior notice, we will inspect the returned package and issue a refund upon receipt. Although there is no restocking fee, we will deduct the cost of the return postage label (£3.35) from your refund.
If the returned item or its packaging shows signs of use, damage, or staining, we may deduct up to 50% of the order value, or refuse the return entirely, depending on its condition. Examples include damaged tags, stained, modified or damaged packaging, or missing components.
For faulty, incorrect, or damaged items, please contact us before sending anything back so we can attempt to resolve the issue directly. If we agree that a return is necessary due to our error, we will provide you with a pre-paid return label.
Products that have been modified or damaged through customer action are not eligible for return. This includes, but is not limited to, items that have been cut, trimmed or otherwise altered (such as a tarpaulin or pond liner resized to your specifications), or any product showing damage beyond normal inspection handling.
All delivery times are estimates and not guaranteed. Orders placed before 1 pm, Monday to Friday (excluding bank holidays), will be dispatched the same day, while orders placed after 1 pm will be dispatched by the end of the next working day.
If an invalid postcode or address is provided, the order will be cancelled without further notice, as we are unable to modify addresses or print labels for invalid postcodes.
Our standard delivery option is Royal Mail Tracked 48, which typically takes 3–5 business days. If you need your order more quickly, Expedited delivery via Royal Mail Tracked 24 is available, offering a 1–2 business day service.
Large or bulky items may be sent via courier at our discretion and are usually dispatched for next-day delivery. Please note that we only ship to mainland UK addresses; delivery to non-mainland locations, including the Highlands & Islands, may not be available for large or heavy items. If your address falls into one of these areas and you wish to purchase such items, please contact us with your postcode and order details before placing your order. If we cannot ship to you, you are welcome to arrange your own courier for collection.
All products, unless otherwise stated, come with a standard manufacturer warranty against faulty workmanship.
If your product fails within six months of delivery, please contact us with your order reference number, a description of the issue, and clear images illustrating the fault.
Should your item require a return for further investigation, it is your responsibility to arrange and cover postage back to us.
If we are unable to repair the fault, we may offer either a replacement or a full refund.
In cases where the item is inspected and found not to be faulty, or where damage is determined not to be due to manufacturing defects, you will not be entitled to a refund or replacement. We will then either return the item to you via standard post or dispose of it at your request.
You may return any order within 14 days of delivery. As soon as you receive your items, please inspect them carefully, taking reasonable care to keep both the product and its packaging clean and undamaged. If you discover an error or defect after 14 days, we reserve the right to decline your return. If your product fails or breaks after this 14-day time window then your order may be eligible for a warranty claim, please see our warranty information for more details.
To initiate a return, please contact us via our contact form to obtain a return authorisation and the correct returns address (different from the address on your invoice). This can also be done through your 'recent orders' page on your account if you are registered with Shop. Returns sent without prior authorisation will be discarded.
Returned items must be in the same condition in which you received them: unworn or unused, with tags attached and in their original packaging. You must include either a copy of your invoice or a slip with your order reference number inside the parcel. Please be sure not to obscure your return reference number on the label.
If you refuse delivery or reject the parcel without prior notice, we will inspect the returned package and issue a refund upon receipt. Although there is no restocking fee, we will deduct the cost of the return postage label (£3.35) from your refund.
If the returned item or its packaging shows signs of use, damage, or staining, we may deduct up to 50% of the order value, or refuse the return entirely, depending on its condition. Examples include damaged tags, stained, modified or damaged packaging, or missing components.
For faulty, incorrect, or damaged items, please contact us before sending anything back so we can attempt to resolve the issue directly. If we agree that a return is necessary due to our error, we will provide you with a pre-paid return label.
Products that have been modified or damaged through customer action are not eligible for return. This includes, but is not limited to, items that have been cut, trimmed or otherwise altered (such as a tarpaulin or pond liner resized to your specifications), or any product showing damage beyond normal inspection handling.