A 6 inch extension for the 20 inch manhole on a Norwesco underground tank
Part number 63514 is Norwesco's 20 inch manhole extension, 6 inches tall, moulded in black polyethylene. It raises the access opening of a buried tank by 6 inches so the lid finishes closer to grade instead of under it. It is 20 inches across, 6 inches tall and weighs 8 lb. On a septic, holding or cistern tank, the manhole is where the tank is pumped and inspected; an opening that is buried gets dug up every time, and an extension is cheaper than a shovel the second time around. Six inches is the small step in Norwesco's range; longer extensions and full risers with lids exist for deeper settings.
Ordering with the tank? Call 866-418-1777 with the tank part number and the depth to grade, and we put the tank and the right extension on one order, or add it to your cart above.
What to check before you buy
- The opening. 20 inch. This extension is for Norwesco underground tanks with a 20 inch manhole; the tank's own page lists its manhole size and its riser and extension options.
- The depth. Measure from the top of the tank to finished grade. If 6 inches does not close the gap, a taller extension or a riser with its own lid does; tell us the measurement and we will match it.
- The lid. The extension raises the opening; the tank's manhole cover goes back on top of it. Confirm you still have the cover, or add one to the order.
- Drawing. Norwesco's drawing for the extension is linked under Technical Drawing on this page.
Installing it
Fit the extension before backfill, on a clean manhole flange, and follow Norwesco's installation instructions for sealing the joint and for what the backfill around the neck has to be. Keep the lid accessible and keep traffic off it; a manhole neck is not a load bearing point. Mark the location on the site plan so the next person can find it without a probe.
Shipping
This part ships by UPS, 8 lb in a 20 by 20 by 6 inch carton, from the nearest of Norwesco's plants in Griffin, Georgia; Hanford, California; Owego, New York; Sheldon, Iowa; Tooele, Utah; Washington Court House, Ohio; or Washougal, Washington. The listed price is before freight; the freight cost estimator gives the cost to your ZIP. Ordered with the tank, the extension travels with it.
Freight and documents
LTL freight is quoted to your ZIP with the freight cost estimator or by phone at 866-418-1777. The listed price is before freight.
Technical drawing (PDF) for Norwesco 63514.
See this tank
Product video. Watch the Norwesco 20 Inch Manhole Extension - 6 Inch Tall video (60 seconds) with dimensions, fittings and shipping notes.
Ready to order?
Add it to your cart at the top of this page, get LTL freight to your ZIP, request a written quote, or call 866-418-1777. The listed price is before freight.
