Will 3/4″ bath fill taps fill up a bath any faster? Absolutely, as long as the water lines in your home are 3/4,” which is likely not the case. Almost all homes will have 1/2″ water lines in residential construction. You may find 3/4 ” water lines in multi housing like apartment buildings but it is reduced to 1/2″ and 3/8″ before the faucets. Claims made by walk in tub companies that their tubs will fill faster are very misleading. Walk-in tubs with similar dimensions will take the same amount of time to fill. In the average home a tub’s flow rate will be 4 – 7 gallons per minute.
What determines the fill time more than taps, is a home’s water pressure and bather size.
Water pressure is controlled by a regulator and can be set to raise or lower a homes pressure, but other variables can effect water pressure like the type of water lines used. Copper fittings are soldered to the outside diameter of copper piping maintaining better water flow where plastic fittings are connected using the inside diameter of pipe reducing flow.
It is important when buying a walk-in tub to get the right size for your body. A very small person in a bath too big, will wait longer for the tub to fill, compared to a much larger person using the same size tub. This is due to the amount of water a bather’s body displaces.
Depending on the tub and bather size and a homes water pressure, fill time will vary. To know how long it will take to fill a tub. Take a pail, place it under your tub’s spout and record the time it takes to fill. Divide the gallons by the seconds it took to fill the bucket then times 60. This will give you the flow rate per minute. Example: Using a four US gallon pale. It took 45 seconds running bath water temperature to fill up. Four divided by 45 gallons is .088 gallons per second. Times .088 by 60 = is 5.28 gallons per minute flow rate.
For an approximation of the amount of water your body will displace and the amount of water you will need, use one gallon of water for every ten pounds of body weight. For instance if the tub you are considering has the capacity to hold 60 gallons of water and you weigh 150 pounds, then your body will displace approximately 15 gallons of water and you’ll need about 45 gallons to fill the tub to its limit.