--- title: Watts RD-100-R Overflow Roof Drain With 2-In. External Water Dam Specs description: Find Watts RD-100-R overflow roof drain with 2-in. external water dam specifications, outlets, dome types and accessories. --- Search our inventory of drains, drain parts, safety and roofing equipment, and accessories. [Shop Now](https://hy-techroof.com/products/). - [ About ](https://www.hy-techroof.com/about-hy-tech/) - [ Contact ](https://www.hy-techroof.com/contact-hy-tech/) - - [![Hy-Tech Roof Products](https://resources.hy-techroof.com/hubfs/Logos/Hy-Tech%20Logo_rgb_maroon_480.png) ](https://www.hy-techroof.com) [**](https://www.hy-techroof.com/login.php) [**](https://www.hy-techroof.com/cart.php) ** ** [![Hy-Tech Roof Products](https://resources.hy-techroof.com/hubfs/Logos/Hy-Tech%20Logo_rgb_maroon_480.png) ](https://www.hy-techroof.com) [**](https://www.hy-techroof.com/cart.php) - - # Watts RD-100-R Overflow Roof Drain With 2-In. External Water Dam Specs *Dimensional data is subject to manufacturing tolerances and change without notice.*   ### **![watts-rd-100-r.png](https://cdn11.bigcommerce.com/s-7wb5vs0sib/product_images/uploaded_images/watts-rd-100-r.png "watts-rd-100-r.png")** **Specifications: **The Watts Drainage RD-100-R is an epoxy-coated, cast-iron overflow roof drain with flashing clamp. It includes an integral 2-in. high external water dam; self-locking polyethylene dome; and no hub (standard) outlet. | **Pipe Size (in.)** | | --- | | 2" (-2) | | 3" (-3) | | 4" (-4) | | 5" (-5) | | 6" (-6) |   ### Outlet Types - No-Hub Outlet (-NH) - Push On (-P) - Threaded Outlet (-T) - Inside Caulk (-X) ### Optional Body Material - PVC Body w/ Socket Outlet (-60) - ABS Body w/ Socket Outlet (-61) ### Accessories - Galvanized Body and Flashing Clamp (-13) - Aluminum Dome (-K80) - Sump Receiver (-B) - Rough Bronze Dome (-K81) - Underdeck Clamp (-D) - Stainless Steel Mesh Covered Dome (-K83) - Adjustable Extension Flange (-F) - Vandal Proof Dome (-L) - Stainless Steel Ballast Guard (-GSS) - Side Outlet (2, 3, 4-in. only) (-SO) - Ductile Iron Dome (-K) - Buy American Compliant (-US) - Galvanized Dome (-K13) - Adjustable Internal Water Dam (-W) - Ductile Iron Low Dome (4-in. high) (-K40) [![New Low Josam 21500 Drain Ring Pricing](https://resources.hy-techroof.com/hs-fs/hub/10783/file-1351163948.png)](https://blog.hy-techroof.com/cs/c/?cta_guid=9a3ec447-4d81-480d-bef0-ca9c22f26691&signature=AAH58kGU-dNvPVvvzZGevWvH1CJ60YrcVw&placement_guid=f0dfd59f-fed0-4ce5-930a-01b19c581cd9&click=c458082c-30db-4efa-8b74-b83c2476a54e&hsutk=dea9f5163d373c9a69a4227b619175b9&canon=https%3A%2F%2Fhy-techroofdrains.com%2Fwatts-rd-100-specs-outlets-options&utm_referrer=https%3A%2F%2Fwww.google.com%2F&portal_id=10783&redirect_url=APefjpHL01Fg4lOcEnr2gEjzgdqvJdG1dC8lS4fOdBHTjfeq5JscQvu64xVM5LPXAS7vbusP5meU6bUxVCHDKOvNZFZGnk1QQIomd-PWCz7kpC7KtJZVcyUwyCOGt1XQUsmwmH43QewrZywTE6wTu5oSCS6JhJov_BDwGICH9NgHWwLS-OF3Ep4ne4InFFUIAw0VT38y01TzBXjgNwCblilpJofxd7w2z7Og92lcLGIN1EAKnQ7pPEJ7p0PmeFVNVlNYTuoxAakb1Oq2uIDTMHpyMr4XCY1zB_Lw-U04XkEiU8TRNSMKZLs&__hstc=57397045.dea9f5163d373c9a69a4227b619175b9.1658485514868.1658492358282.1658512534412.3&__hssc=57397045.2.1658512534412&__hsfp=1542169609) - [Drains](https://www.hy-techroof.com/products/drains/) - [Zurn](https://www.hy-techroof.com/manufacturers/zurn/) - [Smith](https://www.hy-techroof.com/manufacturers/j-r-smith/) - [Josam](https://www.hy-techroof.com/manufacturers/josam/) - [Wade](https://www.hy-techroof.com/manufacturers/wade/) - [Marathon](https://www.hy-techroof.com/manufacturers/marathon/) - [Olympic](https://www.hy-techroof.com/manufacturers/olympic/) - [Equipment](https://www.hy-techroof.com/products/equipment) - [Garlock](https://www.hy-techroof.com/manufacturers/garlock/) - [Leister](https://www.hy-techroof.com/manufacturers/leister/) - [All Seasons / Grizzly](https://www.hy-techroof.com/manufacturers/all-seasons-equipment/) - [Hennes-Johnson](https://www.hy-techroof.com/manufacturers/hennes-johnson/) - [Gator](https://www.hy-techroof.com/manufacturers/gator-roofing-equipment/) - [Roofmaster](https://www.hy-techroof.com/manufacturers/roofmaster-products-company/) - [Safety](https://www.hy-techroof.com/products/safety) - [Leading Edge](https://www.hy-techroof.com/manufacturers/leading-edge-safety/) - [Tie Down Manufacturing Ingenuity](https://www.hy-techroof.com/manufacturers/tie-down-manufacturing-ingenuity/) - [Malta Dynamics](https://www.hy-techroof.com/manufacturers/malta-dynamics/) - [Resources](https://resources.hy-techroof.com) - [Account](https://www.hy-techroof.com/login.php) - [The Drain Wizard](https://resources.hy-techroof.com/ask-the-drain-wizard) - [FAQ](https://resources.hy-techroof.com/faq) - [Blog](https://resources.hy-techroof.com/blog) - [Roof Drain Specs](https://resources.hy-techroof.com/roof-drain-specs-and-diagrams) - [Video Library](https://resources.hy-techroof.com/video-library) - [About](https://www.hy-techroof.com/about-hy-tech/) - [Contact Us](https://www.hy-techroof.com/contact-hy-tech/) - [About Hy-Tech](https://www.hy-techroof.com/about-hy-tech/) - [Service and Repairs](https://www.hy-techroof.com/service-and-repairs/) [800-635-0384](tel:8006350384) **Hy-Tech Products **10035 Broadview Road, Broadview Heights, OH 44147 [info@hy-techroof.com](mailto:info@hy-techroof.com) [800-635-0384](tel:8006350384) **Hy-Tech Products **10035 Broadview Road, Broadview Heights, OH 44147 [info@hy-techroof.com](mailto:info@hy-techroof.com) © 2026 Hy-Tech Products, Inc. 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