Below are some web links that we use and think that you might find to be helpful:

Aeromonas (Method 1605)	http://www.epa.gov/nerlcwww/index.html
Bacteriophage (EPA Method 1601 / 1602)	http://www.epa.gov/nerlcwww/index.html
Cryptosporidium / Giardia (EPA Method 1623)	http://www.epa.gov/nerlcwww/index.html
EPA LT2 Web Site Home Page	http://www.epa.gov/ogwdw/lt2/index.html
EPA 503 Rule (Biosolids)	http://www.access.gpo.gov/nara/cfr/waisidx_03/40cfr503_03.html
EPA Office of Reasearch and Development	http://www.epa.gov/ord/
EPA Home Page	http://www.epa.gov/
EPA Office of Ground Water and Drinking Water	http://www.epa.gov/safewater/
EPA Rule Implementation Milestones and Requirements	http://www.epa.gov
Legionella (CDC)	http://www.cdc.gov/ncidod/dbmd/diseaseinfo/legionellosis_g.htm
Legionella (OSHA)	http://www.osha.gov/dts/osta/otm/legionnaires/index.html
National Environmental Methods Index	http://www.nemi.gov
NWRI Guidelines	http://www.nwri-usa.org
USGS Water Information Site	http://water.usgs.gov/waterwatch