Internet
Industry News
Backflow.com
Water Online - An Online Magazine for Industry Professionals.
Waternet - News and product information.
Waterworld - A resource for the municipal water and wastewater industries.

B to B Ecommerce
WaterDesk - An Online Marketplace and source of news and product information
ChemicalDesk - "at ChemicalDesk, you will find everything you need to serve all the chemical requirements of the water  treatment and pulp & paper industries."
    Briscnet - Global market place for a wide variety of construction related products.

Products
Pipes and Fittings
Ductile Iron Pipe and Fittings
US Pipe - Good online catalog cannot be downloaded.
Tyler - Excellent Adobe Acrobat Catalog can be downloaded.
Griffin - Online Catalog
PVC C-900
PW Pipe
Uponor - No catalog or product description.
J-M Pipe - Product Info, No catalog
Certainteed - Some product info and specifications but no Catalog
PVC Schedule 40
Polyethelene
PW Pipe
Certainteed
Steel
Ameron - Ameron is a principal producer of pipe in the United States and an acknowledged world leader in pipe technology.  Ameron produces custom designed, quality-controlled pipeline systems ranging in diameter from 12 to 144 inches and more.
Northwest - Since 1966, Northwest Pipe Company has been a leading manufacturer of welded steel pipe.
In line Valves
Mueller - Excellent Adobe Acrobat Manuals, Forms and Catalog. Can be downloaded.
Hydra-Stop -  Product Info, No catalog
Control Valves
Cla-Val - Downloadable Catalog
Meters
Sparling - Product Information
Badger - Downloadable Catalog (Adobe Acrobat)
Backflow Prevention
Backflow.com - more backflow related links!
Conbraco -
Febco - Product Information, CAD Drawings, Technical Support, etc.
Watts Regulator Company - PDF files available
Zurn/Wilkins - specializes in the fields of backflow prevention and water pressure reduction. PDF catalog
Cla-Val - Downloadable Catalog
Joint Restraint and Connections
Ebaa Iron - Product Info, AutoCAD drawings
Dresser -  markets a complete line of piping specialties for the natural gas, water distribution and general industrial markets. The broad product line includes pipe couplings and fittings, pipe repair clamps and sleeves, expansion joints, flange adapters, service connectors and saddles, and valves, among other piping products.  
Tools
Software

Construction


Organizations
AWWA - American Water Works Associations
DIPRA -  Ductile Iron Pipe Research Association
NFPA - National Fire Protection Agency
EPA