Don’t Let Your Pool Dry Up!
Have you ever wondered much water evaporates from a pool? Evaporation is likely the culprit to blame for your pool’s vanishing act. Learn exactly how much water your pool can lose, what factors drive faster evaporation rates, and simple strategies to reduce water loss so you can enjoy worry-free swimming all season long.
How Significant Is Water Loss From Pool Evaporation?
How much water evaporates from a pool depends on a lot of factors. On average, a standard-size residential swimming pool in a typical climate loses around 1⁄4 inch of water per day simply from evaporation. This translates into a loss of roughly:
- 2 inches of water per week
- 8 inches per month
- As much as 30 inches over an entire summer!
For larger commercial pools or those located in hotter, drier regions, these numbers can be even higher. Without paying attention and taking preventative action, you might come back from a vacation to find your once relaxing oasis has transformed into little more than a giant puddle!
Several key factors dictate exactly how fast water evaporates from your pool, which we’ll explore next.
What Impacts Your Pool’s Rate of Evaporation?
Many different elements contribute to determining how quickly water evaporates from your swimming pool. The most significant include:
Pool Surface Area
It makes intuitive sense that a larger pool with greater surface area exposed to air allows more space for water to transition into vapor. Doubling the surface size could potentially double the rate of evaporation.
For example, an average 24-foot (7.3 m) round above-ground pool has about 400 square feet (37 m2) of surface area. Compare that to a large inground kidney shaped pool measuring 40 x 20 feet (12 x 6 m) with over 800 square feet (74 m2) of exposed water that can evaporate.
Air and Water Temperature
Higher temperatures, both in and out of the pool, energize water molecules allowing them to more easily reach the gaseous state of water vapor. For every 18°F (10°C) increase in temperature, the evaporation rate doubles!
This is why pools in hot climates like Phoenix, Las Vegas, and Palm Springs require much more monitoring and topping off compared to cooler northern regions. The intensity of the desert sun rapidly heats pool water, accelerating evaporation speed.
Humidity
The amount of moisture already present in the air impacts evaporation potential. The lower the relative humidity, the more capacity and driving force exists to pull additional moisture from the pool.
Dry southwestern states experience sustained periods of low humidity. Whereas tropical climates consistently see abundant atmospheric moisture curbing evaporation by up to 30-40% compared to arid regions.
Wind Speed
Just like rapidly blowing over a cup of hot coffee accelerates cooling, wind flowing over a pool surface speeds evaporation through improved air circulation and moisture removal.
Calm summer days allow pool water to rest with less turbulence for reduced evaporation effects. Meanwhile, springs in windy Chicago might blow away an extra 1⁄8 inch (0.3 cm) of water or more per day.
Sun and Shade
Direct sunlight exposure heats up pool water, increasing evaporation rates compared to shaded areas around the pool perimeter. Significant portions of shade can cut water loss by up to 20%.
Trees, covers, and structures all help limit radiant heating and evaporation. Even simple steps like installing large umbrellas over lounge chairs prevent localized hot spots.
Okay, now that we know why pools lose water, let’s explore just how much they can realistically evaporate.
Estimating Your Pool’s Total Water Loss and how much water evaporates from a pool
We already revealed the average pool loses about 2 inches per week, but how can you estimate evaporation amounts customized for your specific pool’s unique scenario?
Here is a simple equation to model water loss rates:
Evaporation Rate = Pool Surface Area x Evaporation Factor x Time
To perform this calculation, you’ll need to gather:
- Your pool’s surface area in ft2
- The average daily local evaporation rate in inches/day (search your city here)
- Time frame of interest (per day, week, month, etc.)
Example Evaporation Rate Calculation
Let’s demonstrate using real numbers for a common backyard pool scenario:
Pool Dimensions: 24 ft diameter above-ground pool
Surface Area: π x (12 ft)2 = ~400 ft2
Location: Phoenix, AZ
Daily Summer Evaporation Rate: 0.91 in/day
Time Period: 1 month (~30 days)
* Rate is higher than national average due to hot & dry Phoenix climate
Now, performing the evaporation rate calculation:
Daily Water Loss = 400 ft2 x 0.91 in/day = 364 in3 (*converts to gallons below)
Monthly Water Loss = 364 in3 x 30 days = 10,920 in3 = 73 ft3
73 cubic feet x (7.48 gal per ft3) = ~550 gallons lost per month from evaporation
Therefore, accounting for the hot Arizona climate, this 400 square foot pool loses over 500 gallons of water per month on average simply due to evaporation!
Now that you can quantitatively value pool water loss, let’s discuss ways to reduce evaporation and save your precious aquatic resource.
Actionable Strategies to Minimize Pool Water Evaporation
Managing evaporation not only conserves water and saves you money on chemicals and refilling, but also helps in maintaining proper pool water balance by preventing rapid fluctuations.
Here are 5 simple and effective tactics to employ:
Invest In a Pool Cover
A fitted pool cover creates a protective barrier limiting air access and evaporation up to 90%. This represents the single most impactful thing you can do to save water. Durability varies significantly between cover fabric types based on material density, strength, and weave style.
The most protective and longest lasting covers use a 400-denier woven polyester core with UV inhibitors between interlocking layers of polyethylene film. This combination prevents up to 95% of total evaporation while lasting 5+ years before needing replacement.
Inexpensive bubble covers may only reduce water loss by 50-70% and deteriorate rapidly after 1-2 seasons. Weigh cost vs effectiveness when selecting the ideal cover for your pool.
Utilize Solar Blankets
Floating solar blankets trap heat while limiting air exposure at the surface, reducing evaporation by 50%. Added benefits include reduced heating costs and extended swimming seasons by warming pools up to 8-10°F.
Solar rings connect together like giant bubbles and float on the surface. Choose thicker 8-10 mil blankets for maximum heat retention and evaporation protection. Just be diligent rolling up blankets before swimming to prevent tearing over time.
Strategically Schedule Swimming Times
Aim to swim early or late in the day during cooler periods rather than midday when the sun is intense. Limiting use during peak heat minimizes splashing and water loss through evaporation by up to 30% compared to highly active daytime pool enjoyment.
Add Shade Elements
Incorporate shade structures, umbrellas, vegetation, or other features that protect parts of the pool from direct sunlight to create cooler microclimates at the surface. Simple temporary shade solutions reduce evaporative water loss 10-25% depending on coverage area.
Integrated custom designed shade using beams, sails, and strategically placed plants can cut total water replenishment needs 40-50% annually. Bonus benefit – shade also protects swimmers from intense sun exposure!
Maintain Proper Water Chemistry
Balanced water chemistry improves surface tension and stability. Pool water kept near the Langelier Saturation Index with adjusted pH and alkalinity also evaporates up to 20% slower. Why? The mineral components form an invisible layer protecting the underlying liquid water.
Find pools with clear water literally feel softer and smoother against your skin. The soothing feeling comes from proper saturation balance and that same equilibrium also slows evaporation. Plus, clean water just feels great enhancing the swimming experience.
Frequently Asked Pool Water Evaporation Questions
Still have lingering questions? View common evaporative concerns below:
FAQ’s
Question | Answer |
---|---|
How much water does the average pool lose per day? | Most pools lose around 1⁄4 inch of water per day on average due to evaporation. This equates to roughly 8 inches per month. |
What factor has the greatest impact on pool water evaporation rate? | Pool surface area and temperature have the largest influence on determining evaporation from pools. Consider a cover for the greatest savings possible. |
How can I check my pool’s evaporation rate? | Measure the change in water level over a set time frame using pool skimmer marks. Divide by surface area and time to get the loss rate. Alternatively, use our provided equation. |
Do indoor pools also lose water through evaporation? | Yes, indoor pools evaporate significantly slower than outdoor pools but some loss still occurs. Indoor humidity levels largely dictate rates. |
What is the best way to cut down on pool water evaporation? | Pool covers work best, blocking up to 90% of potential loss through evaporation when fitted properly. Durability varies based on material density and weave. |
Question | Answer |
---|---|
How much water is evaporated from a pool in a day? | The amount of water evaporated from a pool in a day varies based on factors like temperature, humidity, wind speed, and pool surface area. On average, pools can lose about 1/4 to 1/2 inch of water per day due to evaporation. |
Why is my pool losing 1/2 inch of water a day? | Losing 1/2 inch of water a day from a pool is typically due to evaporation, especially in hot, dry, or windy conditions. However, if these conditions don’t apply, it could indicate a leak. |
How do I know if my pool is leaking or evaporating? | To determine if your pool is leaking or just evaporating, you can perform a simple bucket test. Fill a bucket with pool water, place it on a pool step, and mark the water levels inside and outside the bucket. After a few days, if the water levels have dropped equally, it’s evaporation. If the pool water level drops more than inside the bucket, it’s likely a leak. |
Why is my pool water evaporating so fast? | Pool water can evaporate quickly due to several factors: high temperatures, low humidity, strong winds, and a large pool surface area. Additionally, lack of cover and increased pool usage can accelerate evaporation. |
Conserve Water and Keep Your Pool Happy
In the end, evaporation causes all pools to steadily lose water over time when exposed to sun and air. By grasping the magnitude of this invisible drain on your pool along with leveraging preventative strategies shared here, you can take control to maximize enjoyment while minimizing upkeep costs and hassles involved with continual refilling.
Plus, proactively guarding your aquatic asset saves precious resources for more sustainable swimming pleasure for years to come. Even when accounting for the inevitability of some water loss, understanding the contributing factors allows adjusting your behavior or pool environment to take back control.
The key is shifting perspective to realize evaporation doesn’t have to be an annoyance, but rather an optimizable parameter through purposeful planning. With this knowledge in hand, you can relax poolside both today and for countless sunny seasons ahead while responsibly preserving every possible drop!