In-wall toilet cisterns hide the tank and plumbing behind a wall or within a support frame, leaving a cleaner look around a wall-hung toilet. The right choice depends on more than appearance: you’ll need to confirm the frame and cistern suit your toilet, wall construction, water supply, and planned flush plate. These five GROHE options vary in frame details, flush controls, connection points, and stated pressure requirements, so check the product specifications and installation requirements before you buy.
Table of Contents
Quick Comparison
| Product | Key Features | Best For |
|---|---|---|
| GROHE Solido 2in1 WC 1.13m | Rapid SL frame, dual flush, low-noise features | Buyers prioritizing a complete frame-and-cistern system |
| GROHE Solido WC Element | Adjustable 6–9L flush, start-stop function, adjustable height | Installations where adjustable flushing is useful |
| GROHE 38661000 Concealed Cistern | Three flush modes and multiple supply connection positions | Projects that need flexible connection options |
| GROHE 38987000 Concealed Flushing Cistern | High-pressure specification and concealed design | Shoppers seeking a straightforward cistern option |
| GROHE 38863000 Concealed Cistern | Multiple flush modes, top water connection, vinyl-fleece plaster base | Installations planned around a top water connection |
Our Picks: Best In Wall Toilet Cisterns reviews
1. GROHE Solido 2in1 WC 1.13m: Best Complete Frame-and-Cistern System
This Solido 2in1 package combines a concealed cistern with a 1.13-meter Rapid SL frame for a wall-hung toilet. That makes it a useful starting point if you want the tank and support system together rather than sourcing those parts separately. GROHE states that the frame is certified to hold up to 400 kg.
Its dual-flush system offers a choice of 3 or 6 liters, or 3 and 5 liters depending on the ceramic toilet body. The smaller flush button can also stop a full flush early. GROHE lists Whisper technology, decoupled piping, and a noise level of 21 dB(A); the stated sound level and flush performance are product specifications, so installation and the selected toilet may affect the finished setup.
The kit also includes a SpareFlush function that provides an extra 3 liters of water, plus ToolFree connections for the water supply, flexible hose, and inspection shaft. The main drawback is that it is not a one-size-fits-all purchase: verify toilet compatibility, wall and plumbing conditions, and the flush plate arrangement before ordering. The listed product information is also less detailed about connection positions than it is for some of the other cisterns here.
Pros:
- Combines a frame and cistern in one system.
- Dual flush offers several stated volume combinations.
- Includes low-noise design features and an early-stop flush.
- Frame is certified to hold up to 400 kg.
Cons:
- Flush volume can depend on the ceramic toilet body.
- Compatibility and installation conditions need careful checking.
Verdict: Choose the Solido 2in1 if you want a feature-rich frame-and-cistern package and have confirmed that its dimensions and connections suit your installation.
2. GROHE Solido WC Element: Best for Adjustable Flush Settings
This GROHE Solido WC Element is a wall-mounted toilet element with a concealed cistern. Its flush quantity is adjustable from 6 to 9 liters, and it supports both two-volume flushing and a start-stop function. Those controls offer flexibility, though the stated range is higher than the 3-liter partial flush listed for the Solido 2in1 above.
The element is adjustable in height and is described as quick and flexible to mount. GROHE lists a load capacity of up to 400 kg. These details may make it worth considering for a project where height adjustment matters, but the supplied product information does not provide a full set of dimensions or connection positions.
Compared with the first pick, this model has a simpler stated feature set: it does not list the same low-noise technology, SpareFlush function, or ToolFree connection details. Confirm that the flush range, mounting method, and included accessories match your toilet and installation plan before purchase.
Pros:
- Flush quantity can be adjusted from 6 to 9 liters.
- Offers two-volume and start-stop flushing.
- Height-adjustable element.
- Listed to carry up to 400 kg.
Cons:
- The stated flush range does not include the smaller 3-liter flush noted for some other picks.
- Product details provide limited information about connection positions.
Verdict: Consider this Solido element if you need height adjustment and want control over flush volume, after checking its flush range against your toilet and water-saving goals.
3. GROHE 38661000 Concealed Cistern: Best for Flexible Water Connections
The GROHE 38661000 is a concealed cistern designed for high-pressure systems, with the listing specifying pressure above 1.0 bar. Its pneumatic discharge valve has three operating choices: dual flush, start-stop, or non-interruptible flush. That selection can be helpful when you need to match the flush control to your preferred use.
Connection options are a notable feature. The water supply can be connected from the left, right, back, or top, giving installers several positions to work with. The listing also describes installation as straightforward and says only a small maintenance access is required. It includes a stated five-year manufacturer’s warranty.
This is a cistern rather than the more clearly described frame-and-cistern package offered by the Solido 2in1. Check whether a suitable support frame, flush plate, and other installation parts are included or need to be sourced separately. The high-pressure requirement is also important: confirm your water system meets the specification before choosing it.
Pros:
- Offers three flush operating modes.
- Water supply can connect from four listed positions.
- Requires only a small maintenance access, according to the listing.
- Includes a stated five-year manufacturer’s warranty.
Cons:
- Specified for high-pressure systems above 1.0 bar.
- Frame and other system components may need to be selected separately.
Verdict: The 38661000 is a strong option to investigate when you need flexible supply connections, provided your water pressure and supporting components are compatible.
4. GROHE 38987000 Concealed Flushing Cistern: Best for a Simple Cistern Specification
The GROHE 38987000 is a concealed flushing cistern with a compact feature description: it is specified for high-pressure systems above 1.0 bar, uses durable materials, and is described as easy to install and maintain. It may suit a project where you already know which flush controls and supporting parts you need.
There is less information provided for this model than for the 38661000. The listing does not specify flush modes, water connection positions, or a warranty, so it is harder to compare its controls and installation flexibility on the available details alone. That does not establish that those features are absent; it means you should confirm them with the seller or manufacturer before buying.
Like the other cistern-only options, this product should not be treated as a complete wall-hung toilet system without checking what is included. Confirm frame compatibility, flush plate fit, maintenance access, and the required pressure. For shoppers who need a well-documented choice, the 38661000 provides more specific connection and flush-mode information.
Pros:
- Concealed cistern design.
- Specified for systems above 1.0 bar.
- Listing describes durable materials.
- Installation and maintenance are described as easy.
Cons:
- Available product details do not state flush modes or connection positions.
- Required frame and compatible controls should be verified separately.
Verdict: Choose the 38987000 only after confirming its controls, connections, and included components meet your installation needs.
5. GROHE 38863000 Concealed Cistern: Best for a Top Water Connection
The GROHE 38863000 is a concealed WC cistern specified for high-pressure systems above 1.0 bar. It supports dual flush, start-stop, or non-interruptible operation, giving you a choice of flush behavior. The listed water supply connection is from the top, a detail worth checking against your planned pipe route.
The cistern has a plaster base coating made of vinyl fleece and is listed in alpine white. GROHE also states that it carries a five-year manufacturer’s warranty. These details distinguish it from the 38661000, which lists several possible water inlet positions but does not specify the same finish or top-only connection in its supplied description.
The main limitation is that the product information does not list the same range of connection positions as the 38661000. If your plumbing comes from another direction, do not assume it can be rerouted or adapted without checking the installation instructions. Also confirm whether the frame, flush plate, and any other required parts are included.
Pros:
- Supports dual flush, start-stop, or non-interruptible operation.
- Top water connection is clearly specified.
- Includes a vinyl-fleece plaster base coating.
- Includes a stated five-year manufacturer’s warranty.
Cons:
- Specified for systems above 1.0 bar.
- Top-only connection details may not suit every plumbing layout.
Verdict: The 38863000 is worth considering when a top supply connection fits your plan and you have verified the pressure and system components.
How to Choose an In-Wall Toilet Cistern
Check whether you need a cistern or a complete frame system
Some products in this group are described as cisterns, while the Solido 2in1 is explicitly presented as a frame-and-cistern system. A cistern alone may not provide every part needed to support a wall-hung toilet or finish the installation. Read the included-parts list and confirm whether you need to buy a frame, flush plate, or other components separately.
Match the frame and cistern to your toilet
Do not assume that every concealed cistern works with every wall-hung toilet. Confirm the model’s dimensions, mounting arrangement, flush controls, and compatibility with your chosen ceramic toilet. For the Solido 2in1, GROHE notes that flush volume can vary with the ceramic body, so check the combination before ordering.
Compare flush options and water volume
Flush controls differ across these models. The Solido 2in1 lists a 3/6-liter or 3/5-liter dual flush, while the Solido WC Element lists an adjustable 6–9-liter range and start-stop operation. Other cisterns list dual flush, start-stop, or non-interruptible modes. Choose based on the specifications of your toilet and the flush behavior you want, rather than assuming the same setting applies to every model.
Verify water pressure and inlet direction
Two cisterns in this selection specify systems above 1.0 bar, while the others do not provide the same pressure detail in the supplied information. Check your plumbing pressure against the manufacturer’s requirements. Also compare the listed supply positions: the 38661000 lists left, right, back, or top connections, whereas the 38863000 specifies a top connection.
Plan the wall, frame, and service access
A concealed cistern needs a suitable place inside or behind the finished wall, and a wall-hung toilet requires an appropriate support arrangement. Check the installation instructions for wall type, frame placement, finished depth, and access for maintenance. A small inspection opening is noted for the 38661000, but access needs can vary by model and installation.
Review the flush plate and maintenance details
Confirm that the flush plate or control you want is compatible and included. The product descriptions do not provide the same level of detail about plate compatibility for every pick, so check before purchase. Also consider how the cistern can be reached for servicing once the wall is finished; access through the flush opening or another planned service point may depend on the system design.
Check the complete package and warranty terms
Compare what is actually included, not just the product title. The listings for the 38661000 and 38863000 state a five-year manufacturer’s warranty, while the supplied details for the other products do not state the same warranty information. Review the current listing and manufacturer documentation for included accessories, warranty coverage, and any installation conditions.
Frequently Asked Questions
What is an in-wall toilet cistern?
It is a toilet tank designed to sit behind a wall or within a concealed installation. The visible area is reduced, while the cistern and, in some systems, the support frame remain hidden after installation.
Do these products include a wall-hung toilet?
The supplied product information describes cisterns or toilet elements, not a complete toilet bowl. Check each listing carefully to confirm whether a ceramic toilet, frame, flush plate, and installation accessories are included.
Are all five cisterns suitable for low-pressure plumbing?
No such conclusion can be made from the supplied specifications. The GROHE 38661000 and 38863000 are listed for pressure above 1.0 bar. For the other models, verify the pressure requirements in the manufacturer’s documentation before purchase.
Which option lists the most water connection positions?
The GROHE 38661000 lists left, right, back, or top water supply connections. The 38863000 specifies a top connection. Check the product instructions to confirm how those positions work with your plumbing layout.
Which model has the lowest stated flush volume?
The Solido 2in1 lists a dual-flush combination of 3 and 6 liters, or 3 and 5 liters depending on the ceramic toilet body. Confirm the appropriate setting for your specific toilet.
Can a concealed cistern be installed as a do-it-yourself project?
Installation depends on the wall, plumbing, frame, toilet, and local requirements. The product listings describe some systems as easy or flexible to install, but those statements do not replace the installation instructions. If you are unsure about the structure or plumbing, consult a qualified installer.
Which product is the best overall choice?
The Solido 2in1 is the most complete option in this group based on the supplied description because it combines a frame and cistern and lists several flush and noise-control features. It is not automatically the right fit for every project, so verify the dimensions, toilet compatibility, connections, and included parts first.
Final Recommendation
For a feature-rich frame-and-cistern package, start with the GROHE Solido 2in1, then confirm that its size and flush settings suit your toilet. If your priority is flexible water connection placement, the GROHE 38661000 has the clearest connection-position details. For any model, check pressure requirements, frame and flush plate compatibility, included parts, and maintenance access before you buy.
