Types of Waterbed Mattresses: Softside, Hardside and More

Key takeaways

• Softside waterbeds look like standard mattresses and use foam rails and zip covers, while hardside waterbeds sit inside a rigid frame that defines their shape.
• Motion control is created by internal baffles and fibre layers, ranging from free‑flow designs like the InnoMax Sanctuary free‑flow mattress through to highly waveless models.
• Deep‑fill and dual‑chamber options can offer more customised support and temperature control, especially for couples or people with back discomfort.
• Most waterbed mattresses are compatible with heaters, but temperature must be matched to the design and used safely for long‑term comfort.
• Understanding the construction, motion level and maintenance needs of each type makes it much easier to choose a waterbed that really suits your sleeping style.

Softside waterbed mattresses

Softside waterbed mattresses are designed to look and behave more like conventional mattresses while still providing the floating feel of water support. Instead of being enclosed by a rigid wooden frame, the water bladder sits inside a “soft” structure made from foam rails and a fabric cover.

Construction and foam rails

A typical softside mattress uses high‑density foam rails around the perimeter to give the bed its shape and edge. These rails are important for several reasons: they make it easier to get in and out of bed, they provide sitting support along the edges, and they help protect the vinyl water chambers inside from everyday knocks.

Inside the foam rails you will usually find either one large water bladder or two separate bladders for dual systems. Above and around the water there may be layers of fibre, foam or quilted padding to soften the feel. Everything is wrapped in a zip‑off cover, often with a plush top quilt, so that from the outside the mattress is hard to distinguish from a standard pocket spring or foam model.

Covers, liners and maintenance

The cover on a softside waterbed is more than just cosmetic. It protects the vinyl from body oils and abrasion, and the top panel is often removable for washing. Beneath the water chamber there is typically a safety liner, designed to catch any leaks and protect the bed base. On softside designs this liner is hidden inside the cover, which keeps the look tidy and helps noise reduction.

From a maintenance point of view, softside waterbeds can be easier to live with than hardside beds. The raised foam rails help keep bedding in place, and the conventional mattress profile means fitted sheets usually work well. You still need to add water conditioner to the mattress and occasionally burp air from the system, but the day‑to‑day routine is similar to caring for a traditional mattress with a mattress protector.

Comfort, support and ideal users

Softside waterbeds are popular with people who want the adaptable support of water without changing the look of their bedroom. The foam rails and top layers slightly reduce the feeling of being “in” the bed and add a touch of firmness around the edges. Many softside models are designed with back support in mind, using strategic fibre layering to create more resistance under the lumbar region.

If you are concerned about back pain or mobility, softside designs are often a practical starting point, as they have a more familiar feel and sitting edge. For more detail on support and posture, it is worth reading a dedicated guide on choosing a waterbed mattress for back pain relief before committing.

Hardside waterbed mattresses

Hardside waterbed mattresses are the classic style many people picture: a large vinyl water chamber sitting inside a sturdy wooden frame. The “hard” in hardside refers to this frame, which contains and shapes the mattress, rather than the feel of the water itself.

Frames, liners and shape control

In a hardside system the water mattress fills the frame from edge to edge. There are no foam rails because the timber or composite frame provides the structure. Under the mattress there is usually a safety liner that folds up the sides of the frame to catch any leaks. The frame edges act as a natural sitting area and keep bedding tucked in, but they also create a more pronounced step when getting into bed.

Because the frame defines the size, hardside waterbed mattresses tend to follow waterbed‑specific dimensions rather than standard mattress sizes. This is important to bear in mind if you are replacing a mattress in an existing frame, as you will need to match both the length and width of your current setup.

Comfort, depth and motion feel

Without foam rails and thick comfort layers, hardside mattresses often give a purer waterbed experience. The water can move more freely, and you may feel a deeper sense of flotation. Depending on the internal construction, this can range from lively motion in a free‑flow model to a gentle, slow‑responding surface in a waveless design.

Because the sleeping area stretches right to the frame edges, hardside beds can feel roomy, especially in larger sizes. However, some people find the high frame sides make them feel more enclosed. If you like the idea of a traditional waterbed feel and do not mind the dedicated frame, a hardside mattress can be very rewarding, especially for those who enjoy a spacious, cocoon‑like sleeping area.

Motion control: free‑flow to waveless

One of the defining characteristics of any waterbed mattress is how much the water moves when you shift your weight. This motion is controlled by the internal design: baffles, fibre layers and sometimes foam inserts all work together to dampen or shape the waves created by movement.

Free‑flow waterbed mattresses

Free‑flow mattresses are the simplest type: essentially a large vinyl chamber filled with conditioned water and little or no internal structure. When you move, the water moves with you in rolling waves that can last for several seconds. For some sleepers this feels wonderfully soothing and weightless; for others, it can be too lively.

A typical example of this style is a free‑flow queen mattress such as the InnoMax Sanctuary free‑flow waterbed, which relies entirely on the water itself for contouring and support. Free‑flow models are often preferred by long‑time waterbed fans or people who like to feel cradled by the water’s movement.

Semi‑waveless and waveless designs

To reduce motion, manufacturers add internal baffles or layers of fibre that slow down the movement of water. Semi‑waveless mattresses still allow a noticeable but shorter‑lasting wave, while fully waveless models may settle very quickly after movement. The amount of damping is sometimes described as a percentage, or by how many seconds the wave continues after someone rolls over.

Waveless designs can be more comfortable for light sleepers and couples, especially if one person moves frequently during the night. They may also provide a more consistent level of support for people with back discomfort, as the body does not need to adjust to ongoing motion. The trade‑off is that you lose some of the classic waterbed sensation, and the mattress can feel slightly firmer because of the internal structure.

If you are unsure which motion level suits you, imagine how you feel in a gently rocking boat versus a very still one. If you find movement relaxing, a free‑flow or lightly baffled mattress may appeal; if you prefer stability, look for a more waveless design.

Deep‑fill vs low‑profile waterbeds

Another key difference between waterbed mattress types is the depth of the water chamber. Deep‑fill mattresses hold more water and usually sit higher, while low‑profile or shallow‑fill designs reduce overall thickness and can feel slightly firmer.

Deep‑fill waterbeds

Deep‑fill mattresses typically allow the water level to reach close to the top of the frame or cover. This creates a pronounced floating sensation, as the body can sink more evenly into the water. In hardside beds, a deep‑fill design can accentuate the classic waterbed feeling, while in softside models it can make the mattress feel more enveloping.

The extra water also increases the bed’s overall weight, which is worth considering if your bedroom floor has any load concerns. Deep‑fill designs can benefit from careful temperature control because the larger volume of water holds heat very efficiently once warmed.

Low‑profile and shallow‑fill designs

Low‑profile waterbeds use a thinner water layer, which reduces weight and lowers the height of the mattress. These designs can suit bedrooms where a tall bed would dominate the space or for people who prefer a slightly firmer, less enveloping feel. In softside beds, shallow‑fill chambers are often combined with more foam or fibre comfort layers to fine‑tune the overall firmness.

Because there is less water to move, low‑profile designs can also feel more controlled, even in free‑flow versions. They tend to respond a little more like a conventional mattress, which may appeal to anyone transitioning from a traditional bed who still wants the adaptability of water support.

Dual‑chamber waterbeds for couples

Couples often have different firmness, temperature and motion preferences. Dual‑chamber waterbed mattresses are designed to address this by splitting the bed into two separate water bladders side by side, usually within a single cover.

Benefits and adjustments

Because each side can be filled to a different level, one partner can enjoy a slightly firmer feel while the other prefers more float. Motion transfer is also reduced, as movement on one side does not send waves directly across to the other. In some systems, each side may even have its own heater, allowing personalised warmth.

This flexibility makes dual‑chamber designs especially attractive for couples where one partner is significantly heavier, sleeps hotter or needs extra back support. It allows fine adjustments without compromising comfort for the other person. The main consideration is that setup takes a little more care, as you need to balance two separate chambers and sometimes two heaters.

Softside vs hardside dual setups

Both softside and hardside waterbeds can be built as dual systems. In softside mattresses, the foam rails and cover help keep the two bladders neatly aligned and can disguise any slight height differences between sides. In hardside frames, the central division is sometimes more noticeable, but many sleepers quickly adapt.

For partners who are unsure whether a shared or dual system is best, it can help to think about typical sleeping patterns. If one of you tosses and turns or wakes frequently, a dual‑chamber waveless design will likely offer the calmest night’s sleep. If you both sleep deeply and enjoy the sensation of shared movement, a single‑chamber mattress may be perfectly adequate.

Heaters and temperature control

One of the quiet pleasures of waterbed ownership is precise temperature control. Because water holds heat so consistently, once a mattress is warmed it tends to stay comfortably stable. Most waterbed mattresses are designed to work with compatible under‑mattress heaters that sit on the platform beneath the vinyl.

Compatibility and safety

Heater compatibility depends on the size and type of waterbed. Hardside mattresses generally use heaters that sit directly on the solid base beneath the safety liner and mattress. Softside designs use similar heaters but may require specific wattage or shapes to match the foam cavity and base material. It is important to use a heater that is designed for waterbed use and to follow the manufacturer’s guidelines carefully.

Controllers vary from simple analogue dials to digital thermostats with timers and remotes. For example, some cooling and temperature‑controlled pads, such as a water‑cooled mattress with remote control, demonstrate how precisely water temperature can be adjusted for sleeping comfort, although these are generally used on top of standard mattresses rather than as full waterbeds.

Balancing warmth and breathability

While many people love a gently warmed waterbed, it is also possible to use cooler settings or supplement with breathable mattress pads to fine‑tune your sleep climate. Lightweight covers and natural fibre bedding can prevent overheating, while thicker duvets and mattress protectors help retain warmth when needed.

The goal is to achieve a neutral, cosy surface that supports muscle relaxation and joint comfort without feeling overly hot. Adjustments are usually made season‑by‑season, but once dialled in, a waterbed’s temperature tends to feel very consistent from night to night.

Specialised water mattresses and pads

Alongside full‑size waterbed mattresses, there is a growing category of water‑filled pads and cooling mats designed for specific purposes such as camping, travel, student accommodation or summer heat relief. These are not traditional waterbeds, but they share similar principles: water is used to distribute pressure and regulate temperature.

Cooling and travel‑friendly water mats

Compact water‑cooled mattress pads are often designed to sit on top of an existing bed or camp cot, providing a cooler surface in warm conditions. A typical example would be a single‑bed water cooling mat for camping or student rooms, which uses a small volume of water to absorb heat from the body.

These products generally require far less water than a full waterbed and can be emptied and stored away when not needed. They are useful for experimenting with the feel of water support or for adding comfort to temporary sleeping arrangements, though they do not replace the structural support of a proper mattress and base.

How they differ from full waterbed mattresses

Unlike dedicated waterbed mattresses, cooling mats and portable water pads do not rely on a rigid frame or thick foam rails. They are usually thinner, more flexible and focused on surface comfort rather than deep support. Motion control is basic, as the small water volume tends to limit large waves naturally.

They can, however, demonstrate how responsive water can be to changes in body temperature and pressure, giving a taste of water‑based sleep technology without the commitment of a full frame, heater and dedicated base.

Choosing the right type for your needs

When deciding between softside and hardside waterbeds, different motion levels, deep or shallow fill and single or dual systems, it helps to focus on how you actually sleep. Side sleepers may enjoy the way deep‑fill or slightly freer‑flowing mattresses cushion shoulders and hips, while back sleepers often appreciate the even support of a more waveless design.

If you value a conventional bedroom look and easy bedding changes, a softside mattress with a medium motion level can be a practical all‑rounder. For those who want the most authentic waterbed experience and have space for a dedicated frame, a hardside deep‑fill mattress with your preferred wave control offers a very distinctive feel.

Couples should consider dual‑chamber options if you have noticeably different preferences for firmness or temperature. Light sleepers may want to prioritise waveless or semi‑waveless interiors to avoid being disturbed by partners moving in the night. It can also help to think long term: a balanced, medium‑motion softside bed is usually easier to adapt to than an extreme free‑flow or ultra‑firm setup.

Conclusion

Waterbed mattresses have evolved into a varied category, from discreet softside designs that blend into any bedroom through to classic hardside frames with a deep, floating feel. Within these broad types, you can fine‑tune motion level, water depth, dual‑chamber layouts and temperature control to match your personal sleep style.

Exploring options such as a free‑flow system like the Sanctuary free‑flow waterbed mattress or adding a dedicated cooling or heating pad, similar in concept to a water‑cooled remote‑controlled mattress pad, can help you understand what combination of features feels best.

By taking time to understand the main types of waterbed mattresses and how they influence comfort, support and maintenance, you can choose a setup that remains comfortable and practical for many years, rather than simply chasing a novelty.