How much water does a bath use in Litres?

Taking a bath is one of life’s simple pleasures. There’s nothing quite like soaking in a warm tub after a long day to help you relax and unwind. However, with concerns over droughts and water scarcity rising, it’s important to be aware of your bath’s water usage.

Quick Answer

The average bath tub holds 150 litres (40 US gallons) of water. However, the amount of water used can vary based on the size and shape of your tub. Generally, baths use between 100-200 litres (26-53 US gallons) of water.

How Much Water Does a Standard Bathtub Hold?

A standard bathtub in most countries holds approximately 150 litres (or 40 US gallons) of water when completely filled. The standard length of a bathtub is 1.7 metres (5.5 feet) while the width ranges from 0.6-0.7 metres (2-2.3 feet). The average depth is 0.4 metres (1.5 feet).

Based on these standard dimensions, a basic calculation estimates that most standard tubs hold around 150 litres when filled to capacity. However, it’s important to note that tub sizes can vary, which affects water usage.

Factors That Affect Bathtub Water Usage

While 150 litres is a reasonable estimate for most tubs, several factors can alter how much water a bath actually uses:

  • Tub dimensions – Larger, deeper tubs require more water to fill up.
  • Tub shape – Unique shapes like corner tubs may hold more or less water.
  • Water depth – Filling to different depths requires more or less water.
  • Bather displacement – The bather’s body mass displaces some water, lowering the amount used.

Because of these factors, the actual water usage of a bath can range from 100-200+ litres depending on your unique tub size and bathing preferences.

Average Water Used Per Bath

While a full 150 litre tub is possible, most baths do not actually require this much water. Here are some general averages for water used per bath:

  • Half-full tub – 75 litres
  • Two-thirds full – 100 litres
  • Three-quarter full – 120 litres
  • Filled to overflow drain – 150 litres

The average bath is around 100-120 litres according to most sources. However, some luxury spa tubs may exceed 200 litres when completely full. The best way to determine your actual water usage is to fill your tub to your normal bathing level and measure how much water is required.

Water Usage Comparison With Showers

How does bathing water usage compare to showering? Here is a look at average water volumes:

  • 5 minute shower – 40 litres
  • 10 minute shower – 80 litres
  • 15 minute shower – 120 litres
  • Average bath – 100-120 litres

A standard 10 minute shower uses approximately the same amount of water as the average bath. However, shower times can vary significantly. Short 5 minute “navy” showers use less water, while long luxurious showers may exceed the water usage of a bath.

Factors That Impact Shower Water Usage

As with baths, several factors influence how much water is used during a shower:

  • Duration – Longer showers use more water.
  • Flow rate – High pressure shower heads have higher flow rates.
  • Low-flow models – Special low-flow shower heads use less water.
  • Shower stall size – Larger shower stalls may require more water to wet surfaces.
  • Temperature – Heating water requires longer shower times.

Considering these factors, a typical 10-15 minute shower will use about the same amount of water as a standard bath. But shower water usage can vary significantly between households.

Tips For Reducing Bath Water Usage

If you enjoy bathing but want to reduce your water usage, here are a few tips:

  • Take “navy” showers – Partially fill the tub and top up as needed.
  • Reuse bath water – Consider reusing your bath water for other purposes like watering plants.
  • Install a flow restrictor – This limits water volume from the faucet.
  • Take shorter baths – Reduce your bathing time to lower water volumes.

With some minor adjustments, you can still enjoy a relaxing bath without using excessive amounts of water.

How Much Water Does a Spa Tub Use?

Spa tubs, also known as jetted tubs, are designed for luxury soaking and hydrotherapy. Because of their larger size and jet pumps, spa tubs require significantly more water than standard tubs.

Here are the typical water capacities of different spa tubs:

  • Two-person model – 200 to 300 litres
  • Three-person model – 300 to 400 litres
  • Four-person model – 400 to 600 litres

In addition, spa tubs need to have water pumped through their hydrotherapy jets. This requires the tub to be completely full during use, using the tub’s maximum water volume.

So while a standard bathtub may use around 150 litres, a large 4-person luxury spa tub can use over 600 litres of water per use when completely filled. The increased water usage is the tradeoff for the additional soaking comfort and massage benefits.

Tips For Reducing Spa Tub Water Use

Here are some ways to enjoy your spa tub while conserving water:

  • Set a timer – Limit your soak time to reduce water volumes.
  • Reuse water – Drain and refill for multiple uses.
  • Lower fill level – Partially fill if not using jets.
  • Insulate tub – Retains heat longer allowing shorter soaks.

While spa tubs use more water than regular tubs, there are ways to maintain an indulgent soak while minimizing your water footprint.

How Much Water Does a Hot Tub Use?

Hot tubs provide luxurious spa benefits at home. But operating a hot tub requires significant water volumes. Here is a look at how much water a hot tub uses.

Typical Hot Tub Capacities

  • 2-person hot tub – 500 to 700 litres
  • 4-person hot tub – 800 to 1,200 litres
  • 6-person hot tub – 1,400 to 2,000 litres

These capacities are when the tub is completely filled. Hot tubs must be full to safely operate the hydrojets and heat the water effectively.

Amount of Water Loss

In addition to the initial fill volume, hot tubs continually lose water over time and need to be topped up. Sources of water loss include:

  • Splash out – Water splashing over the sides.
  • Evaporation – Heat causes water to evaporate.
  • Filter backwashing – The filtration process drains some water.
  • Drain and refill – Tubs need periodic complete drains.

Total water loss can range from 380-950 litres per month depending on tub size and frequency of use. This needs to be replaced by topping up the hot tub throughout the month.

Tips For Conserving Hot Tub Water

Strategies to minimize hot tub water usage include:

  • Install a cover – Reduces evaporation and splash out.
  • Recycle backwash water – Use for lawns or plants.
  • Only drain when necessary – Refill 3-4 times a year.
  • Fix leaks promptly – Prevent excess water loss.

While hot tubs require extensive water fill and top-ups, there are ways to maximize water efficiency while enjoying your home spa.

How Much Water Does a Plunge Pool Use?

For those looking to bring resort-style luxury home, plunge pools allow swimming and soaking in a compact footprint. But how much water do these small pools use? Here is a look at plunge pool water capacities.

Typical Plunge Pool Sizes

Plunge pools are designed to be all-immersed lounging pools. Common dimensions include:

  • Length – 3 to 4 metres
  • Width – 2 to 3 metres
  • Depth – 1 to 1.5 metres

This gives a typical plunge pool a capacity of around 8,000 to 15,000 litres when filled. Larger or custom-designed plunge pools may exceed 20,000 litres.

Monthly Evaporation Rates

In addition to initial fill requirements, plunge pools lose significant water each month through evaporation in warm climates. Evaporation rates range from:

  • Temperate region – 2,500 litres per month
  • Tropical region – 4,500+ litres per month

This evaporation needs to be continually replaced to keep the plunge pool operating safely.

Tips For Saving Plunge Pool Water

Strategies to minimize water usage for plunge pools include:

  • Use a pool cover – Reduces evaporation when not in use.
  • Monitor water level – Top up based on exact losses.
  • Repair any leaks – Prevent excess water loss.
  • Consider greywater – Reuse water from the home.

While plunge pools have high initial fill and ongoing top-up requirements, conservation steps can reduce waste and cost.

How Much Water Does Filling My Tub Use Compared to Operating Appliances?

Filling your bathtub uses a significant amount of water. But how does this compare to the water usage of common household appliances?

Appliance/Fixture Average Water Used
Bathtub 150 litres (full)
Shower 40-80 litres (10 mins)
Toilet flush 4-9 litres per flush
Dishwasher 15-30 litres per load
Washing machine 100-150 litres per load
Hand washing dishes 20-40 litres

As you can see, filling a standard bathtub uses approximately the same amount of water as doing a load of laundry. Showering for 10 minutes uses about the same amount as running a dishwasher.

While baths may seem indulgent, they generally use less water than essential cleaning appliances. Focusing on reducing usage across all household water fixtures is key for conservation.

How Can I Estimate My Unique Bath’s Water Usage?

If you want to determine your own bath or tub’s specific water usage, here is a simple process:

  1. Measure the length, width and depth dimensions of your bath or tub in metres.
  2. Use an online calculator to estimate the volume in litres based on those dimensions.
  3. Fill your tub to your normal bathing level.
  4. Use a measuring cup to estimate the amount of water used in litres.

This will provide a personalized estimate of how much water your unique bathtub or tub requires. You can then use this information to set goals for reducing your bath water usage if desired.


Enjoying a relaxing soak doesn’t have to come at the cost of high water usage. While baths use more water than quick showers, there are many ways to reduce your bathing water footprint. With some minor adjustments and conservation awareness, you can sustain the simple pleasure of bathing responsibly.

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