Can I Drain My Pool and Refill It? Everything You Need to Know About Pool Draining

If you’re a pool owner, you’ve likely asked yourself at one point or another, “Can I drain my pool and refill it?” Whether you’re dealing with water quality issues, planning a renovation, or preparing for winter, the question is valid and important. But the answer isn’t as simple as “yes” or “no.” Pool draining comes with risks, costs, and specific circumstances that must be evaluated. In this comprehensive guide, we’ll explore when it may be necessary to drain your pool, the best practices, and the often-overlooked dangers that many homeowners neglect.

Understanding Pool Draining: What It Involves

Draining a swimming pool is exactly what it sounds like — the complete or partial removal of water from the pool to perform maintenance, repairs, or cleaning. However, pool professionals often advise against this unless absolutely necessary, because improper draining can lead to serious structural damage or costly repairs.

There are two primary types of pool draining:

• Total drain: complete removal of all water from the pool basin.
• Partial drain: removing only a portion of the water, typically for repairs, filter cleaning, or water chemistry corrections.

Each method carries different purposes and risks. For instance, total draining is typically only recommended for renovations, major repairs, or in emergencies like extreme algae infestation that cannot be resolved through chemical treatment. On the other hand, partial draining is more commonplace and can be safely done as part of regular pool maintenance.

Reasons to Drain a Pool

Sometimes draining is the only viable option. Below are the most common reasons pool owners consider this step:

1. Poor Water Quality

If the pool water is excessively high in:

• Chlorine
• Salinity (for saltwater pools)
• Hardness or alkalinity

Then partial or complete draining might be necessary to restore balance without the continued overuse of chemicals. However, repeated draining to fix chemical imbalances can cause long-term damage, especially in in-ground pools.

2. Algae Infestations

Severe algae outbreaks—especially black algae that embeds in plaster surfaces—can require professional draining and pressure washing. This is often accompanied by acid washing (which should never be performed without expert assistance).

3. Renovations or Repairs

Major structural damage like cracks in the shell, necessary resurfacing, or plumbing issues underneath an exposed area might require full drainage for safe repairs.

4. Winterization

In freeze-prone areas, draining is often part of winterizing an above-ground pool. In-ground pools, however, typically only require a partial drain.

5. Excessive Rainfall or Flooding

Heavy rainfall can raise the water level and alter chemical balance. Sometimes draining a few inches helps reestablish equilibrium.

Why Pool Draining Can Be Dangerous

Contrary to popular belief, draining a pool isn’t just a matter of flipping a switch. There are legitimate safety concerns and even legal considerations to be aware of.

Potential Structural Damage

In-ground pools require careful consideration when draining. Water inside the pool helps counteract hydrostatic pressure from groundwater. If drained improperly — especially during periods of heavy rain or high water tables — the pool can float or pop from the ground, causing significant damage to walls, plumbing, and tile.

What Causes a Pool to Float?

Hydrostatic uplift is the phenomenon where ground water beneath the pool pushes the empty shell toward the surface. This happens because:

• Empty pools lack the counterweight of water.
• Groundwater levels rise, especially after heavy rain or winter snowmelt.
• Inadequate draining infrastructure (like hydrostatic relief valves) isn’t in place.

Once a pool has floated, repairs can cost tens of thousands of dollars — far more than keeping water in the shell would have.

Equipment and Liner Damage

For vinyl-lined pools, draining can lead to wrinkles, stretching, or tears once the water is reintroduced. Fiberglass pools may crack due to improper supports, especially if left empty for long periods.

Legal and Environmental Issues

In many places, pool water requires proper disposal due to the presence of chlorine, salt, algaecides, and other chemicals. Discharging untreated chlorinated water into storm drains, local rivers, or even sewer systems can be illegal and result in fines.

Always check with local regulators or your water authority about where and how to safely offload pool water.

Can I Safely Drain My Pool?

The answer depends on several factors:

1. Pool Type
2. Regional Climate and Moisture Levels
3. Season and Groundwater Table
4. Purpose of Draining
5. Ownership of Proper Equipment

In general, in-ground pools should be drained only under professional supervision, especially if the purpose involves total evacuation.

Draining Above-Ground vs In-Ground Pools

How to Drain Your Pool Safely — Step by Step

If you’ve determined that draining is necessary and safe, here’s how to proceed properly.

Step 1: Test and Check Water Chemistry

Before draining, test your water for:

• pH
• Chlorine levels
• Alkalinity
• Hardness

This helps determine whether partial draining could be sufficient or if a full dump is necessary.

Step 2: Choose the Right Pump

To avoid damaging your filtration system, never drain through the pool pump filter. Instead, use a submersible pump specifically designed for draining pools. These pumps move water quickly and effectively, and are available at most hardware stores.

Step 3: Ensure Safe Disposal

Before you start, locate municipal disposal guidelines:

• Some areas allow draining into sewer cleanouts.
• Others require dechlorination before water can legally enter storm drains.
• Using a hose to drain slowly into your yard may work — as long as water doesn’t flood your landscape.

Step 4: Monitor the Depth

Unless absolute draining is needed for repair or renovation, aim to only drain below the skimmer and return lines. This way, the water still offers structural support while allowing for repairs.

Step 5: Keep Your Pool Covered

If the pool will be empty for more than a day, protect it with a pool cover and fencing, especially if children or local wildlife are in the area.

Step 6: Refill in a Timely Manner

Don’t leave your pool empty for extended periods — especially during:

• Summer heat
• High winds
• Heavy rainfall

Refilling should ideally occur within hours of draining to avoid stress on the structure or liner.

Alternatives to Traditional Draining

Before you decide to pull all the water out, consider alternatives that might resolve your issue without the hazard.

Partial Draining for Chemical Correction

Instead of full draining, you can:

• Drain 20–30% of the water.
• Refill and rebalance chemicals.

This reduces chemical waste and structural stress.

Shock and Circulate Treatments

For most algae and bacterial concerns, a pool shock program combined with filtering and skimming can effectively clear the water without draining.

Water Replacement via Filters

If you’re using saltwater or have high TDS (total dissolved solids), partial draining and replacing with fresh water can help maintain a balanced environment.

Professional Pool Cleaning and Inspection

Sometimes, the issue isn’t the water itself — it’s the filtration system, a cracked pipe, or a circulation problem. Getting a professional inspection might save you from unnecessary and dangerous draining.

Refilling Your Pool After Draining

Once the draining process is complete and the repairs or cleaning has taken place, it’s time to refill. How you do this can be as important as how you drained.

Water Source Considerations

While most pool owners use a garden hose and city water, there may be cost or mineral concerns:

• City water can contain minerals that affect pool chemistry.
• Well water might have iron or similar minerals that stain or discolor.
• Treated water or softened water may be preferable in some areas.

Chemical Rebalancing

Once full, test the water again for:

• pH
• Chlorine levels
• Alkalinity
• Calcium hardness

Balancing these ensures comfort, longevity of equipment, and safety for swimmers.

Filter Start-Up and Circulation

Let your pool filter run for 24–48 hours non-stop after refilling. This ensures even distribution of chemicals and helps eliminate any residual debris or contaminants introduced during the draining process.

When to Consult a Pool Professional

Even if you’re a savvy DIYer, there are some decisions where professional guidance can prevent expensive mistakes.

Professional Input Is Recommended For:

• In-ground pools in high water table zones.
• Renovation or concrete resurfacing projects.
• Major repairs involving structural cracking, leaks, or plumbing.

Pools are complex systems, and professional pool technicians have the tools, knowledge, and experience to drain or repair them without lasting harm.

Additionally, hiring a professional means you’re less likely to:

• Void pool warranties
• Commit legal violations
• Create liability or safety risks

If you’re uncertain about your ability to safely and effectively manage draining, seek out expert help. It’s often far cheaper than facing the consequences of a mistake later.

Key Takeaways: Draining and Refilling Your Pool

We’ve covered a lot in this in-depth exploration, so let’s highlight what’s most important:

• Draining is not inherently bad, but it must be done cautiously.
• Total draining poses serious structural risks and is best left to professionals, especially for in-ground pools.
• Always test your water before and after draining to determine if it is necessary.
• Dispose pool water properly by following local laws to avoid fines.
• Refill promptly after draining to prevent structural damage.
• Consider chemical balancing and partial drainage techniques before turning to a full pool dump.

Final Thoughts

So, going back to our original question: “Can I drain my pool and refill it?” The short answer is yes — but the long answer is only under the right conditions and with the right precautions in place.

Whether you’re dealing with excessive chemical waste, winterizing your above-ground oasis, or preparing for a long-overdue resurfacing job, knowledge and preparation go a long way. Draining may seem like a simple solution, but as with many pool-related issues, it has complexities and consequences that shouldn’t be taken lightly.

If in doubt, call in a local pool service professional. Your pool is a major investment, and treating it like one can prevent avoidable and costly damage. Always prioritize safety over convenience, and you’ll keep both your pool and property in excellent shape for years to come.

Can I drain my pool and refill it without professional help?

While it is technically possible to drain and refill your pool yourself, the process involves several considerations that may require professional expertise. Using a sump pump or hiring a water removal service to drain the pool properly is essential to avoid damaging the pool structure. Additionally, local regulations may require permits for draining large amounts of water, especially concerning sewer or storm drain usage. Refilling the pool also takes time, typically 8–12 hours with a garden hose, and you must test and balance the new water properly before use.

If you have an inground pool, especially in an area with a high water table, there is a risk of the pool “popping out” of the ground during draining due to hydrostatic pressure. This can cause significant damage and expensive repairs. For this reason, professionals often recommend keeping at least some water in the pool during draining, particularly for concrete or fiberglass pools. If you’re unsure about local laws, the type of pool you have, or how to safely handle the water balance afterward, hiring a professional is a wise decision.

Why would I need to drain my pool?

There are several valid reasons why a pool owner might consider draining their pool. One of the most common is to perform repairs or maintenance on the pool’s structure, such as fixing leaks, replacing tiles, or resurfacing. Draining may also be necessary in cases of severely unbalanced water chemistry that cannot be corrected through dilution or other less drastic methods. Additionally, some pool owners choose to drain and refill their pools after a major storm or contamination event, like a sewage backup or an excessive algae bloom.

However, draining a pool should not be taken lightly. It is not necessary to fully drain a pool for routine cleaning or winterization, as modern filtration systems and chemical treatments allow for partial water replacement and maintenance. Frequent full draining can lead to structural damage, increased wear on pool surfaces, and unnecessary expenses for water and refilling chemicals. It’s always a good idea to consult a pool professional to determine whether draining is truly necessary for your situation.

How often should I drain my pool?

Most pool experts recommend draining and refilling a swimming pool every 3 to 5 years. This time frame helps manage the buildup of total dissolved solids (TDS) in the water, which can interfere with the effectiveness of chemicals and potentially cause staining or scaling. However, the exact timing depends on several factors, including the size of the pool, how frequently it’s used, the source of the water, and the effectiveness of your filtration and chemical maintenance routine.

In some cases, partial draining followed by refilling may be sufficient to maintain balanced water chemistry. For example, some pool owners may opt to drain 20–30% of the pool and replace it annually instead of doing a full drain every few years. Seasonal changes, particularly in areas with high evaporation rates or mineral-heavy source water, may also influence how often draining is needed. Always monitor your water chemistry through regular testing to help determine when a partial or full drain is appropriate.

Will draining my pool save money in the long run?

Draining a pool does not necessarily save money and can be more expensive than expected. The cost of water removal, replumbing the water supply, and rebalancing the chemicals after refilling can add up quickly. Moreover, if the draining causes structural damage—such as cracks or shifting in an inground pool—repair costs can be substantial. In many cases, maintaining proper chemical levels, regularly cleaning the filtration system, and performing partial water replacements can help extend the time between full drains, ultimately saving money.

However, in situations where water chemistry has become severely imbalanced or where high levels of contaminants are present, draining may be more cost-effective in the long term. Persistent issues like scaling, cloudiness, or unresponsive pH can make ongoing maintenance difficult and inefficient. In these cases, a full or partial drain is a strategic investment in restoring the pool’s water quality and making chemical maintenance more effective. The key is to approach draining as a necessary maintenance step—not a routine or cost-saving measure.

What are the risks of draining an inground pool?

Inground pools are particularly vulnerable to damage during the draining process. One of the primary risks is the effect of a high water table in the surrounding soil, which can cause the empty pool to “pop” out of the ground. This problem is especially common in areas with heavy rainfall or poor drainage. The upward pressure from groundwater can lift the entire structure, leading to cracks in the shell, plumbing damage, or shifting of the walls, all of which are expensive to repair.

Another risk involves the damage that can occur to the interior finish of the pool. Without water to apply even pressure against the walls and floor, structural strain can lead to surface cracks or tile detachment. Fiberglass and concrete pools are particularly sensitive to this issue. In addition, if the pool is drained in extreme weather conditions—like intense heat—the shell can expand unevenly, further increasing the potential for damage. To minimize these risks, it’s often recommended to keep the pool partially filled or to drain it only under professional supervision.

How long does it take to refill a drained pool?

The time it takes to refill a pool depends on several factors, including the pool’s size, the water pressure from the source, and whether you’re using a garden hose or professional water delivery service. On average, filling a standard-sized inground pool (around 20,000 gallons) with a garden hose can take anywhere from 8 to 12 hours or even longer, depending on the water flow rate. Municipal water systems may require additional permits or restrictions on usage, which could affect the refilling timeline.

To speed up the process without increasing utility bills significantly, some pool owners opt for a bulk water delivery service, which uses large trucks to bring in and pump clean water directly into the pool. This option can often refill a pool in just a few hours. Once the pool is filled, it’s important to circulate the water and test its chemistry—including pH, alkalinity, calcium hardness, and chlorine levels—before swimming. These adjustments can take additional time and may delay the pool’s return to operation for a day or more.

Is there an environmentally friendly way to drain my pool?

Draining a pool can have environmental impacts if not done responsibly, so it’s important to follow proper procedures. Pool water contains chemicals like chlorine and algaecides, which can harm plants, animals, and waterways. Local regulations often require pool owners to dechlorinate the water and test its chemistry before releasing it into the sewer system, storm drain, or onto the landscape. Using a chemical neutralizer or letting the water sit until the chlorine dissipates naturally can help reduce environmental harm.

Additionally, consider reusing the drained water for non-potable purposes such as irrigation, dust control, or cleaning—if it’s free of harmful contaminants. Some municipalities also have guidelines or treatment systems in place for pool drainage. When possible, work with a professional pool service that is familiar with environmental regulations and best practices for pool draining. By following these steps, you can responsibly manage the process and minimize your impact on the surrounding ecosystem.