Pentair T40BW AutoFill Automatic Water Filler – White Lid with Side-Mounted Float Valve
The Pentair T40BW AutoFill is an automatic pool water level control designed for standard in-ground pools. It uses a simple, reliable side-mounted float valve to monitor the pool’s water level and add water as needed, helping prevent low-water conditions that can lead to pump damage, loss of prime, and poor skimmer performance.
Key Features
- Part Number: T40BW
- Product Type: Automatic water filler / water leveler (AutoFill)
- Float Valve: Side-mounted float valve (mechanical level control)
- Lid Color: White
- Purpose: Maintains a more consistent pool water level automatically
Why This Part Matters
- Helps protect pumps and skimmers from running under low-water conditions
- Reduces day-to-day manual topping off (especially during hot, windy, or dry weather)
- Helps keep skimming and cleaner performance consistent by maintaining proper waterline height
Common Reasons to Replace
- AutoFill no longer shuts off reliably (overfilling)
- AutoFill no longer opens when the water drops (low water level issues)
- Cracked housing or damaged lid/deck components
- Float valve sticks, leaks, or is worn from age or debris
Installation Notes
- Typically installed in the deck near the pool, tied into a dedicated water supply line.
- Water level is adjusted by setting the float height per the unit’s adjustment mechanism.
- For best results, verify you have a proper overflow/drain path so the pool cannot overfill during heavy rain or a valve issue.
- If you are not familiar with plumbing local code requirements, installation is best handled by a qualified pool professional.
Related Products
- Search: Pentair T40BW
- Search: Pentair AutoFill
- Search: Automatic Water Fillers
- Search: Pool Water Levelers
- Search: Pool Overflow / Drain Fittings
- Search: Silicone Pool Lubricant
Installation & Maintenance Tips
- Check the AutoFill canister periodically and remove leaves/sand that can interfere with float movement.
- If the unit is slow to fill, confirm your supply valve is fully open and the supply line/strainer (if used) is not clogged.
- If the unit overfills, shut off the supply line and inspect for a stuck float or debris in the valve.
- Keep your pool waterline in the recommended range for proper skimmer function—consistent water level improves circulation and surface cleaning.
Questions about returns? View our return policy.
Hours Of Operation:
Monday - Friday: 7:00 am to 5:00 pm Phoenix Time
Saturday: 8:00 am to 2:00 pm
Sunday: Closed
- We do not ship on Saturday or Sunday.
- Orders totaling more than $300 will require signature confirmation upon delivery.
- We process and prepare orders for shipment within 1 business day. Please note that many other pool supply retailers require 3–5 days of handling time before shipping.
- Orders placed after 1:00 pm Phoenix Time may not be eligible for same-day shipment.
- Expedited shipping options are available at checkout.
Return Policy:
- Products that are received damaged will receive a refund in store credit.
- Most products are eligible for return within 30 days of receipt, except where noted below.
- To initiate a return, please complete an RMA form prior to sending your item back.
- Original shipping costs are non-refundable and will be deducted from the return credit.
- Items returned missing accessories or original packaging, or that are not in the same condition as received, may be subject to a restocking fee of up to 100% depending on the condition of the item upon return.
- Some returns will be charged an automatic 15% restocking fee.
- We are unable to issue refunds for items that have been damaged or rendered inoperable due to installer error.
- Please complete the return form to receive your RMA number and return shipping label.
- Chemical products are not eligible for return under any circumstances.
- The Pentair Colorsync 618031 is not eligible for return.
- Pool cleaners are not eligible for return.
- Opened seals and o-rings are not eligible for return.
- Capacitors are not eligible for return.
- Plastic popup tools are not eligible for return.
- Automation components and circuit boards are not eligible for return.
- If a light is returned due to a reported malfunction and is found to be fully operational upon testing, return shipping costs and a restocking fee will be deducted from the refund.
- Orders refused at the time of delivery will be subject to the original shipping costs being deducted from the refund.
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