How Do You Winterize a Pool?
Winterize before nighttime temperatures stay below 32 degrees F — late September to early October in most northern states. Freeze damage to plumbing lines and equipment is the most expensive pool repair there is: water left in the lines cracks fittings and costs $1,000 to $4,000+ in spring repairs. Here is the complete winterization process.
When to Winterize
Winterize before sustained nighttime temperatures drop below 32 degrees F in your area. In most northern US states: late September to early October for the primary winterization; closing before the first hard freeze event is the goal. A pool that freezes with water in the lines: plumbing cracks and fittings split, costing $1,000 to $4,000+ in spring repairs. Winterization timing is one of the most important annual pool decisions. (For more on this, see What Does a Pool Cost to Own? Annual Operating Costs.)
The Winterization Process
1. Balance chemicals 5 to 7 days before closing: adjust pH to 7.4 to 7.6, alkalinity to 100 to 150 ppm, and shock the pool. 2. Lower water level: reduce to 4 to 6 inches below the skimmer (for mesh winter covers) or 6 to 8 inches below (for solid covers). 3. Blow out the lines: use a compressor to blow water out of all plumbing lines (return lines, skimmer lines, drain lines), then plug each line with a winterizing plug. Water remaining in the lines will freeze and crack the fittings. 4. Add winter chemicals: a winter algaecide, a stain and scale inhibitor, and a pool enzyme product. For pools with covers: a chemical float dispenser maintains residual sanitizer through the winter. 5. Remove and store accessories: ladders, rails, diving boards, skimmer baskets. 6. Install the winter cover: a safety cover (ASTM F1346-certified) or a solid winter cover held with water bags or cover anchors. The CPSC’s Pool Safely campaign covers barrier requirements, drain entrapment, and layers of protection.
Professional vs. DIY Winterization
Professional pool closing: $200 to $650 for most residential pools. DIY closing: requires a shop compressor with adequate PSI and CFM to blow out the lines effectively. For homeowners comfortable with the process and who own or can rent a suitable compressor: DIY is feasible. For homeowners in their first pool season: professional closing is strongly recommended — an incorrectly winterized pool’s damage is far more expensive than the cost of professional service. (For more on this, see How to Find a Reliable Pool Cleaning Service.)
Working With a Contractor on This Project
Getting the right outcome on any home services project starts before the work begins. A few consistent practices make the difference between a smooth project and a frustrating one.
Get at least two or three quotes. A single quote gives you no basis for comparison. Two or three quotes reveal the market rate for the work, expose scope differences between bidders, and let you assess contractor communication quality before any commitment is made. The lowest bid is not automatically the best value if the scope is thin or the materials are underspecified.
Ask for licenses and insurance before work starts. Verify current general liability insurance and, for any work involving workers on your property, workers compensation coverage. Licensing requirements vary by state and trade; confirm the specific requirements in your jurisdiction. A licensed contractor who carries appropriate insurance protects both parties if something goes wrong during the project.
Get the scope in writing. A written proposal that specifies materials, labor scope, timeline, what is included (permits, cleanup, disposal), and warranty terms is the foundation of a professional engagement. Verbal agreements on any of these points invite misunderstanding. For any project over $500, written scope is non-negotiable.
Clarify the payment schedule upfront. A reasonable payment schedule ties major payments to project milestones: a deposit at signing, a payment at material delivery or project start, and a final payment at completion after a walkthrough confirms satisfaction. A contractor who requires full payment upfront before work begins is a red flag in any trade.
Making a Confident Decision
The information in this article is designed to help you ask better questions of the professionals you work with, evaluate their answers with more confidence, and understand the decisions involved in this type of home services project. It is not a substitute for professional assessment of your specific home.
Every home is different. Roof slopes, local weather, tree exposure, soil conditions, and existing system condition all affect what the right solution is for your specific situation. The general principles here apply broadly, but a professional who assesses your home in person will give you guidance that accounts for the details that general articles cannot.
When you are ready to move forward, getting at least two or three quotes from licensed, insured, local contractors is the most important practical step. It lets you compare approaches, assess contractor quality, and confirm that the solution proposed matches your specific situation and budget.
Pool Renovation Cost at a Glance
Here is a quick reference for pool renovation costs, from a basic resurfacing to a full renovation with equipment and features.
| Cost Factor | Typical Range | Notes |
|---|---|---|
| White plaster resurfacing | $6 to $8 per sq ft of interior surface | Classic finish, 7 to 15-year lifespan. $6,000 to $15,000 for a standard pool. |
| Quartz aggregate resurfacing (Diamond Brite, Hydrazzo) | $7,000 to $15,000 | Most popular renovation choice, 12 to 20-year lifespan. |
| Pebble finish resurfacing (Pebble Tec, Pebble Sheen) | $10,000 to $20,000+ | Most durable, 15 to 25-year lifespan. |
| Tile and coping replacement | $5,000 to $15,000 | for a standard pool, depending on material choice |
| Equipment package (pump, filter, heater, lights) | $3,000 to $10,000 depending on specifications | |
| Adding a spillover spa to an existing pool | $15,000 to $35,000 | |
| Comprehensive full renovation (resurface + tile/coping + equipment + features) | $30,000 to $55,000 | $15,000 to $30,000 on a small pool and $50,000 to $80,000+ on a large one. Extends the pool’s visual and functional life by 15 to 25 years. |
Cost figures on this page were checked against published pricing on August 29, 2026. How we source cost data.
Renovation is almost always more cost-effective than demolition and new construction ($61,000 to $145,000) for a pool with a structurally sound shell. (For more on this, see What Makes Pool Cleaning Cost More (or Less)?.)
Frequently Asked Questions
Before sustained nighttime temperatures drop below 32 degrees F in your area -- typically late September to mid-October in most northern US states. Closing too early wastes the swimming season; closing too late risks a freeze event before the pool is protected. In-season algae control is more effective while the water is warm, so close when nighttime temps are consistently at or below 60 degrees F.
Water in the plumbing lines freezes and expands, cracking PVC pipes, splitting return fittings, and damaging the pump and filter housings. Freeze damage repair: $1,000 to $4,000 for most residential pools, depending on what cracks and where. Equipment left unprotected (pump, heater, filter): may require full replacement. Proper winterization is one of the most cost-effective maintenance investments for any northern pool owner.
No -- and you should not drain a pool for winter unless absolutely necessary (to repair the surface, for example). A properly winterized pool keeps water in the shell (inground pools need the weight of the water to prevent hydrostatic pressure from lifting the shell out of the ground). Lower the water level to below the skimmer and blow out the lines -- do not completely drain.
Winterize properly (blow out lines, plug returns, lower water level). Run the pump on a freeze protection setting (many pool automation systems include a freeze protection mode that turns on the pump automatically when ambient temperatures approach 32 degrees F). A properly winterized pool does not need to run the pump in winter -- the water in the pool will freeze on the surface, but the freeze does not damage a properly winterized pool.
Safety cover (ASTM F1346-certified mesh or solid): the best option. It prevents debris accumulation, allows rainwater to pass through (mesh) or pump off (solid), and provides a safety barrier. Solid winter covers with water bags: less expensive but require a pump to remove accumulated rain and provide no safety barrier. Avoid: tarps or non-rated covers that cannot support adult weight -- they are not safety barriers and fail in heavy snow and ice loads.