Not every pool needs a 1,500 GPH cover pump. Not every pool is fine with 800 GPH. The right answer depends on how much water your cover collects, how fast it collects it, and how quickly you need it cleared before damage or removal. Here is the calculation and the product comparison that takes the guessing out of the decision.
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Cover Pumps at PoolPartsToGo: Best auto at 800 GPH: B+D 800 GPH Automatic ($69.99) Best value at 800 GPH: B+D 800 GPH Manual ($64.99) Best 1500 GPH (3-yr warranty): B+D 1500 GPH Automatic ($89.99) Best budget 1500 GPH auto: Sunnora 1500 GPH Automatic ($84.99) Lowest price 1500 GPH: Sunnora 1500 GPH Manual ($74.99) Browse all: Pool Cover Pumps at PoolPartsToGo |
Why GPH Is the Only Number That Matters in a Cover Pump
A pool cover pump has one job: remove water before it accumulates to damaging weight or blocks a cover removal. The rate at which it does that job is measured in gallons per hour (GPH). Every other specification on a cover pump, switch type, cord length, base design, is secondary to whether the GPH is high enough for the volume of water your cover collects.
The problem most pool owners face is not buying a pump that does not work. It is buying a pump that works but cannot keep pace with the rainfall rate on their specific cover. A 350 GPH pump during a 2-inch storm on a 20-by-40-foot cover is a losing race: the cover collects roughly 1,000 gallons faster than the pump can remove it. An 800 GPH pump on the same cover in the same storm takes over two hours to clear. A 1,500 GPH pump clears it in about an hour.
The cover cannot tell the difference. It just holds the weight. At a certain point, the weight bows the cover inward, stresses the anchors, and risks dumping sediment-laden water into the pool when you try to remove it. Getting the GPH right is how you avoid that scenario.
How to Calculate the GPH You Actually Need
Step 1: Find Your Cover Area
Your cover area is approximately your pool area plus 2 to 3 feet on each side for overhang. For a rectangular pool, multiply length by width and add the overhang. For a round pool, use the standard circle formula (pi times radius squared). The exact overhang varies by cover brand, but 2 feet per side is a reasonable estimate for most residential solid covers.
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Quick Cover Area Examples: • 16 x 32 pool with 2-ft overhang: cover is approximately 20 x 36 ft = 720 sq ft • 18 x 36 pool with 2-ft overhang: cover is approximately 22 x 40 ft = 880 sq ft • 20 x 40 pool with 2-ft overhang: cover is approximately 24 x 44 ft = 1,056 sq ft • Round 24 ft pool with 2-ft overhang: cover is approximately 28 ft diameter = ~615 sq ft The table below uses the pool dimensions directly (without overhang) for simplicity. Your actual cover volume will be slightly higher due to overhang. |
Step 2: Calculate Water Volume from Rainfall
One inch of rain deposited on one square foot of surface adds 0.623 gallons of water. To find your cover's volume per inch of rainfall: multiply your cover area in square feet by 0.623. For a 20x40 pool cover (800 square feet), one inch of rain adds approximately 499 gallons.
Here is the water volume table for common residential pool cover sizes:
|
Cover Size |
1 Inch of Rain |
2 Inches of Rain |
3 Inches of Rain |
Pump Recommendation |
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14 x 28 ft (392 sqft) |
~244 gal |
~488 gal |
~732 gal |
800 GPH adequate for moderate rainfall. 1,500 GPH for fast clearance before cover removal. |
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16 x 32 ft (512 sqft) |
~319 gal |
~638 gal |
~957 gal |
800 GPH handles light-moderate rain. 1,500 GPH recommended for spring storms. |
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18 x 36 ft (648 sqft) |
~404 gal |
~808 gal |
~1,212 gal |
1,500 GPH recommended. 800 GPH too slow for heavy rain events; cover stress risk. |
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20 x 40 ft (800 sqft) |
~499 gal |
~998 gal |
~1,497 gal |
1,500 GPH required. A 3-inch rain adds nearly 1,500 gallons; 800 GPH takes 2+ hrs to clear. |
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24 x 48 ft (1152 sqft) |
~718 gal |
~1,436 gal |
~2,154 gal |
1,500 GPH required. Consider two pumps for very large covers in high-rainfall areas. |
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Round 24 ft dia (452 sqft) |
~282 gal |
~564 gal |
~846 gal |
800 GPH adequate for most conditions. 1,500 GPH for fast pre-opening clearance. |
Step 3: Match GPH to Volume and Acceptable Clearance Time
Once you know your volume, divide by the pump's GPH to find clearance time in hours. A 16x32 cover with 957 gallons from 3 inches of rain needs 1.2 hours at 800 GPH or 38 minutes at 1,500 GPH. Both are manageable. The question is whether 1.2 hours is acceptable given your cover's weight tolerance and your timeline.
|
Scenario |
800 GPH Clearance |
1,500 GPH Clearance |
Why It Matters |
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16x32 cover, 1 inch rain (~319 gal) |
~24 min |
~13 min |
Either pump handles light rain quickly. 800 GPH is adequate. Choose based on whether you want automatic or manual operation. |
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16x32 cover, 3 inches rain (~957 gal) |
~72 min |
~38 min |
1,500 GPH clears almost twice as fast. If you want the cover cleared before leaving for work after a night storm, this matters. |
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20x40 cover, 1 inch rain (~499 gal) |
~37 min |
~20 min |
Moderate rain on a large cover: 800 GPH is still workable but slower. 1,500 GPH removes it fast. |
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20x40 cover, 3 inches rain (~1,497 gal) |
~112 min |
~60 min |
For spring opening, this is the most common scenario. A 2-hour clearance at 800 GPH vs 1 hour at 1,500 GPH. 1,500 GPH recommended. |
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Pre-opening single session (any size) |
Hours |
1 to 2 hrs |
Planning to pull the cover Saturday? The pump that clears fastest with a morning-to-noon window matters. 1,500 GPH gives you more flexibility. |
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The Rule of Thumb: When to Choose 1,500 GPH Over 800 GPH Choose 800 GPH if: your cover is 18x36 or smaller, your area does not regularly see storms exceeding 2 inches, and you are fine checking the cover manually or using the auto switch to manage a slower drain. Choose 1,500 GPH if: your cover is 18x36 or larger, your area sees frequent or heavy spring rainfall, you want the cover cleared quickly before removal, or you want automated overnight operation on a large cover without worrying about weight accumulation. |
Automatic vs. Manual Cover Pumps
Beyond GPH, the second decision is automatic versus manual operation. This is not just a convenience question. For pool owners who travel, leave the pool unattended for days at a time, or live in areas with frequent overnight rain events, automatic operation is a safety decision for the cover.
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How Automatic Operation Works on the PPTG Models B+D 800 Auto (2-stage): Starts at 2 inches of standing water. Drains to 1/8 inch. Cycles off when water level drops below threshold. Restarts automatically when water returns to 2 inches. Requires no manual action. B+D 1500 Auto (dual switch): Activates at 4.25 inches. Drains to 1/8 inch. Dual float switch design activates slightly higher than the 800 GPH model to prevent cycling during light misting. Best for large covers where you want the pump to run only when there is meaningful water accumulation. Sunnora 1500 Auto (dual switch): Same 4.25-inch activation and 1/8-inch drain as the B+D 1500 Auto. Patented pre-filter sponge design. Manual (B+D 800 Manual, Sunnora 1500 Manual): Plugged in, runs until unplugged or until water drops below 1/8 inch and the motor runs dry. For manual models, you decide when to plug in and when to disconnect. Best for planned sessions when you will be present. |
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When to Leave a Cover Pump Running All Winter An automatic cover pump left plugged in all winter on a covered pool is the lowest-effort way to protect the cover. Leave the B+D 800 Auto or B+D 1500 Auto connected with the discharge hose routed to a drainage area, and the pump handles every rain and snowmelt event automatically throughout the closed season. Remove the pump before adding closing chemicals and reinstall after the pool is covered and chemicals are distributed. |
All Five Cover Pumps at PoolPartsToGo
PoolPartsToGo carries five cover pumps across three GPH tiers (350 GPH, 800 GPH, and 1,500 GPH). The five featured models span the 800 and 1,500 GPH tiers with both automatic and manual options across both brands. Here is the complete specification comparison:
|
Feature |
B+D 800 Manual |
B+D 800 Auto |
B+D 1500 Auto |
Sunnora 1500 Auto |
Sunnora 1500 Manual |
Key Differentiator |
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Price |
$64.99 |
$69.99 |
$89.99 |
$84.99 |
$74.99 |
B+D 800M lowest price; Sunnora 1500M best value at 1500 GPH |
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Was |
$99 |
$119 |
$210 |
$149.99 |
$139.99 |
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GPH |
800 |
800 |
1,500 |
1,500 |
1,500 |
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Switch |
Manual |
Automatic |
Automatic |
Automatic |
Manual |
$5 more for auto (800 GPH); $10 more for auto (1500 GPH) |
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Activates at |
2 inches |
2 inches |
4.25 inches |
4.25 inches |
Manual only |
800 GPH activates earlier; 1500 GPH holds more before starting |
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Drains to |
1/8 inch |
1/8 inch |
1/8 inch |
1/8 inch |
1/8 inch |
All five drain to near-dry |
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Power cord |
25 ft |
25 ft |
25 ft |
25 ft |
25 ft |
All include 25 ft cord |
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Hose |
Adapter only |
Adapter only |
30 ft incl. |
30 ft incl. |
30 ft incl. |
1500 GPH models include 30 ft discharge hose |
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Warranty |
1-year |
1-year |
3-year |
1-year |
1-year |
B+D 1500 only model with 3-year warranty |
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UL Listed |
Yes |
Yes |
Yes |
Not stated |
Not stated |
B+D models confirmed UL Listed |
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Oil-free |
Yes |
Yes |
Yes |
Not stated |
Not stated |
B+D models confirmed oil-free |
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Pre-filter |
Yes |
Yes |
Yes (patented) |
Yes (patented) |
Yes (patented) |
All include pre-filter sponge |
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The B+D 1500 Auto's 3-Year Warranty Is the Lineup's Most Important Differentiator The B+D 1500 GPH Automatic is the only cover pump across all five models with a 3-year warranty. At $89.99 (a $5 premium over the Sunnora 1500 Auto at $84.99), the extended warranty covers two additional seasons beyond the standard 1-year. For a pump that runs unattended outdoors through freeze-thaw cycles, fall debris, and spring storms, the 3-year coverage at that price premium is significant. If the pump fails in year 2 or 3 under normal use, it is replaced. The Sunnora is not. |
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Activation Depth Differences: Why the 800 and 1500 GPH Models Are Different The B+D 800 Auto activates at 2 inches of standing water. The B+D 1500 Auto and Sunnora 1500 Auto activate at 4.25 inches. This is not a disadvantage of the 1,500 GPH models. The higher activation threshold prevents the 1,500 GPH pump from cycling on and off repeatedly during light drizzle or condensation, which is appropriate for a pump its size. The 800 GPH model's 2-inch threshold makes it slightly more responsive to minor accumulation, which suits smaller covers where any water accumulation is meaningful. |
Which Cover Pump Should You Buy?
Here is the decision guide by situation:
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Your Situation |
Best Pick |
Why |
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Small cover (16x32 or under), light to moderate rainfall |
B+D 800 Auto ($69.99) |
Correct GPH for the cover size. Auto operation means it handles overnight rain without you. Best combination of price and convenience at 800 GPH. |
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Small cover, budget is the priority |
B+D 800 Manual ($64.99) |
At $64.99, the lowest-price pump on PPTG. Manual is fine if you can check the cover regularly. $5 savings over the auto version. |
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Large cover (18x36+), any rainfall |
B+D 1500 Auto ($89.99) |
3-year warranty and 1,500 GPH for larger covers. Auto operation plus the longest warranty in the lineup. Best total value for large covers. |
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Large cover, cost-first at 1500 GPH |
Sunnora 1500 Auto ($84.99) |
Same dual auto switch and 1,500 GPH as the B+D. Saves $5. Trade-off: 1-year warranty vs. B+D's 3-year. |
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Hands-on owner who manages pump-down manually |
Sunnora 1500 Manual ($74.99) |
Lowest price at 1,500 GPH. Manual is fine for planned sessions before cover removal. No float switch to maintain. |
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Spring opening, need fastest clearance before pulling the cover |
B+D 1500 Auto ($89.99) |
The 1-hour clearance time on a 20x40 cover gives you maximum flexibility for opening day. Set it running in the morning, cover is clear by noon. |
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Want both: 800 GPH for winter, 1500 GPH for spring opening |
Buy both: B+D 800 Auto + Sunnora 1500 Manual |
Leave the 800 auto on the cover all winter for automatic management. Use the 1500 manual for the final pre-opening session. Total cost: $144.98. |
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The Two-Pump Strategy: Winter Auto + Spring Manual One of the most cost-effective approaches for pool owners who want automatic coverage through the winter and maximum drainage speed at spring opening: keep the B+D 800 Auto ($69.99) running all winter for automatic rain and snowmelt management, then use the Sunnora 1500 Manual ($74.99) for the final planned pump-down session before cover removal. The manual 1,500 GPH clears a large cover faster than the automatic 800 GPH, and you only need the manual for the one day you are present and ready to open. Total investment: $144.98 for a complete winter-through-opening solution. |
Shop Cover Pumps at PoolPartsToGo
800 GPH Models
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B+D (Best 800 GPH Automatic, UL Listed) $69.99 (was $119) BLACK+DECKER 800 GPH Automatic Pool Cover Pump 2-stage automatic switch activates at 2 inches of water and drains to 1/8 inch with no manual intervention. Designed for leaving plugged in all winter for automatic rain and snowmelt management. Pre-filter sponge prevents debris clogs. Oil-free design. UL Listed. 25 ft power cord. Standard hose adapter included. 1-year warranty. Ships free. |
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B+D (Best Value 800 GPH, UL Listed) $64.99 (was $99) BLACK+DECKER 800 GPH Manual Pool Cover Pump Manual operation at the lowest price in the 800 GPH tier. Plug in to run, drains to 1/8 inch. Can begin pumping at 2 inches of water. Extra large 7-inch stabilized base. Pre-filter sponge pad prevents clogging. Oil-free design. UL Listed. 25 ft power cord. Standard hose adapter. 1-year warranty. Ships free. |
1,500 GPH Models
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B+D (Best 1500 GPH, 3-Year Warranty, UL Listed) $89.99 (was $210) BLACK+DECKER 1500 GPH Automatic Pool Cover Pump The only cover pump in the PPTG lineup with a 3-year warranty. Dual automatic float switch activates at 4.25 inches and drains to 1/8 inch automatically. 1,500 GPH clears a 20x40 cover after 3 inches of rain in approximately 60 minutes. Patented pre-filter sponge. Oil-free. UL Listed. 25 ft power cord. 30 ft discharge hose included. Ships free. |
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Sunnora (Best Budget 1500 GPH Auto, $5 Less Than B+D) $84.99 (was $149.99) Sunnora 1500 GPH Automatic Pool Cover Pump Same 1,500 GPH output and dual automatic float switch (activates at 4.25 inches, drains to 1/8 inch) as the B+D model at $5 less. Patented pre-filter sponge. 25 ft power cord. 30 ft discharge hose included. 1-year warranty (versus B+D's 3-year). Best choice when budget is the deciding factor at 1,500 GPH. Ships free. |
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Sunnora (Lowest Price at 1500 GPH, Best for Pre-Opening) $74.99 (was $139.99) Sunnora 1500 GPH Manual Pool Cover Pump The most affordable 1,500 GPH cover pump at PPTG. Manual operation for planned pump-down sessions. Drains to 1/8 inch. Patented pre-filter sponge. 25 ft power cord. 30 ft discharge hose included. 1-year warranty. Best for pool owners who check the cover regularly and want the fastest manual clearance before spring opening at the lowest price. Ships free. |
Frequently Asked Questions
How long will it take my 800 GPH pump to drain my pool cover?
Calculate your cover area in square feet, multiply by 0.623 to get gallons per inch of rain, then divide by 800 to get hours. For a 16x32 pool cover (approximately 512 square feet), 1 inch of rain deposits roughly 319 gallons. At 800 GPH, that clears in about 24 minutes. After 3 inches of rain (957 gallons), clearance takes approximately 72 minutes. Use the water volume table in Section 2 for your specific cover size.
What is the difference between the B+D 800 Auto and the Sunnora 1500 Auto?
Two main differences: GPH (800 vs 1,500) and warranty (1-year on both, but the B+D 1500 Auto, not these two, has the 3-year). The B+D 800 Auto activates at 2 inches; the Sunnora 1500 Auto activates at 4.25 inches. For smaller covers (16x32 and under) in moderate-rainfall areas, the B+D 800 Auto is adequate and lower cost. For larger covers or high-rainfall areas, the Sunnora 1500 Auto's 1,500 GPH clears nearly twice as fast.
Can I leave a cover pump running all winter?
Yes, and for automatic models, that is the recommended approach. Plug in the automatic pump after installing the cover, route the discharge hose away from the pool and foundation, and let it manage every rain and snowmelt event on its own. Remove it before closing chemical treatments and reinstall after chemicals are distributed. The B+D 800 Auto and B+D 1500 Auto are both designed for unattended all-season operation.
Why does the 1500 GPH model activate at 4.25 inches while the 800 GPH model activates at 2 inches?
The higher activation threshold on the 1,500 GPH models prevents constant on-off cycling during light precipitation. A 1,500 GPH pump starting for every drizzle and condensation event would wear its float switch unnecessarily. The 4.25-inch threshold ensures the pump activates when there is meaningful accumulation worth running the larger motor for. The 800 GPH model's 2-inch threshold is appropriate for its smaller size, where 2 inches of water already represents a meaningful portion of what a small cover can hold comfortably.
Is the discharge hose included or do I need to buy one separately?
For the B+D 800 Manual and B+D 800 Auto, a standard hose adapter is included but the discharge hose itself is not. These models connect to a standard garden hose. For all three 1,500 GPH models (B+D 1500 Auto, Sunnora 1500 Auto, Sunnora 1500 Manual), a 30-foot discharge hose is included in the box. The 1,500 GPH models are ready to run with no additional purchase needed.
What happens if the pump runs dry?
All five models are designed to drain to approximately 1/8 inch of remaining water, at which point the float switch (on automatic models) will shut off the pump or the pump naturally loses prime. Running a submersible cover pump briefly at low water levels is designed into the product. Do not run a cover pump for extended periods with the intake completely out of water, as this can cause motor overheating. Monitor the first few uses to confirm normal operation.
Match the GPH to the Cover, Then Match the Switch to Your Schedule
The GPH calculation is the first decision. The automatic vs. manual choice is the second. Every pool owner with a solid cover needs one pump on the cover from closing day through opening day. The five models at PoolPartsToGo cover every combination of size, budget, and operation preference from $64.99 for the most affordable 800 GPH manual through $89.99 for the 1,500 GPH automatic with a 3-year warranty.
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Shop Cover Pumps at PoolPartsToGo: B+D 800 GPH Automatic ($69.99) B+D 1500 GPH Automatic ($89.99) - 3-Year Warranty Sunnora 1500 GPH Automatic ($84.99) |
