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Filling a Traditional Wood Frame Waterbed Mattress

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Things You Will Absolutely Need


A clean hose is used for draining your mattress. Old hoses or garden hoses can introduce bacteria and other things into the mattress. A 25 foot hose may not reach far enough. You may wish to pre-measure hose length.


Faucet Connector / Adapter allows connecting Hose or Venturi Pump to sink

perfect union

The Perfect Union allows connecting a hose to the mattress

venturi pump

The Venturi Pump connects to the faucet.
When the rotating valve on the bottom is in the down position it removes water from the bed.
In the up position it puts water into the bed.


O-Rings keep seals tight, you cannot fill or drain a bed if everything is not airtight.


Waterbed Conditioner should be poured into mattress if it is to be stored for a period of time.

If moving right away you will need to have this so you can set your bed up right away.

If you don't have everything you see above, you are not ready to drain your mattress.

      How to Fill a Waterbed Mattress in a Wood Frame Bed

1  Remove Aerator

From your faucet remove the aerator by unscrewing it. If the faucet does not have an aerator, try another faucet, sometimes a laundry or deep sink may be used. The last choice would be an outside faucet because you want to put warm water into your waterbed mattress.

If the aerator is stubborn, wrap several layers of duct or electrical tape around it to protect it from scratches and use a pair of pliers to loosen the aerator.

faucet aereator  

2  Attach the faucet connector / adapter from your Waterbed Care Kit or Drain Fill Kit to your faucet.

2a   Attach a hose to the faucet connector.

Be sure this is a clean hose.

Hoses that have been stored outside for a period of time, or that have dirt inside them may introduce enzymes, bacteria, or other contamination into your mattress.

If you must use an outside hose, rinse the hose for five minutes by letting water run through the hose into a sink or tub away from any outside dirt, do this prior to using it to fill the mattress.

attaching to faucet

3  Attach the Perfect Union to the end of the waterbed hose.


4  Remove the cap and seal from the mattress fill. Screw the Perfect Union attachment into the fill hole. Be sure it is tight enough yet do not overtighten and strip the threads. A small towel might be handy to soak up any leakage from the filling process.

remove cap  

5  Fill the mattress with about 2" of luke-warm water. This is a good time for any final adjustment.

Once the mattress is full of water it will be impossible to move so check everything carefully. You cannot budge 1200 + pounds of water inside a thin vinyl mattress.


6  Pour in your waterbed conditioner

6a   Continue to fill the bed with warm water until it is 1/4" to 1/2" below the side of the frame boards using warm water. Shut off the water and remove the hose.

Cold water is not approriate for filling a mattress.  Use only warm water. Your waterbed heater can maintain a set temperature but will have a difficult time bringing a cold bed up to temperature. Remember a heater has only a few hundred watts and we are  trying to heat 1200 - 2000 pounds of water.

add conditioner  

7  Burping

Remove the air from inside the mattress. Use a broomstick or other rod, slide it from the head of the bed toward the un-capped fill hole. Remove all the bubbles to prevent noise from the mattress. If you have a Super Burper this will make it much easier since it sits higher than the fill and has a built in check valve. Install the seal and cap.

Be sure broomstick or rod is splinter free.

A new mattress will periodically need to be "burped" to remove the air.

fill level  

8  How much water is enough?

This depends on the style of mattress. The "1/4" to "1/2" below the rail was only an approximation. Adding or subtracting water can change the feel of the bed a great deal.

Use a yardstick, dowel rod or simular item on top of the mattress as an indicator for how full the mattress actually is.

Many people use the old "eyeball" method and usually overfill by a few inches. This negatiively impacts on the comfort level of your mattress and strains the vinyl and shortens mattress life.

With fiberfilled mattresses rated over 95% waveless, more water makes it appear softer and less water makes it appear firmer, the opposite of what you would think.


With a mattress of 90% or less waveless rating, the mattress should be filled to accomodate the largest sleeper for the bed. This is done by measuring with the body. Sit in the middle of the bed. Rock gently to the left and right. If your bottom only touches when you rock from side to side, it is filled the correct amount.

If your bottom is always touching, add water. If your bottom never touches, drain some water.


If you purchased rail caps, this is a good time to put these on.

If you find they are a little too loose later on, they may be secured by glueing hook & pile tape to the rails and the top of the frame.

This is a good time to check everything over for loose tools and other sharp items that might ruin your new waterbed. Check that the frame/decking assembly is centrally located on all four sides.


9  Installing Dual Waterbed Bladders

Similar to above except you alternate filling each dual mattress bladder a little at a time.

Most use two waterbed heaters, one per side. Be sure to not place over seams between deck boards, heater pad can easily be damaged by the seams.

If you fill one mattress fully and then try to fill the second mattress, the first mattress will occupy more space than the second mattress. 

Be sure to install Thermal Divider before filling

Fill the first mattress bladder with about 2 inches of water before switching to the second mattress bladder. Add 2 inches of water to it, then add Waterbed Conditioner

Continue alternately filling each mattress about 2 inches at a time until both mattress bladders are filled.