diff --git a/man/readNWISpCode.Rd b/man/readNWISpCode.Rd
index a5c44f97cdbf437916d2b1396e2ac72d44cd9243..855420453fb157ca4ad08e3c3ecaf7237c11f65a 100644
--- a/man/readNWISpCode.Rd
+++ b/man/readNWISpCode.Rd
@@ -6,7 +6,9 @@
 readNWISpCode(parameterCd)
 }
 \arguments{
-\item{parameterCd}{character of USGS parameter codes (or multiple parameter codes).  This is usually an 5 digit number.}
+\item{parameterCd}{character of USGS parameter codes (or multiple parameter codes).  These are 5 digit number codes
+that can be found here: \link{http://help.waterdata.usgs.gov/codes-and-parameters/parameters}. To get a
+complete list of all current parameter codes in the USGS, use "all" as the input.}
 }
 \value{
 parameterData data frame with all information from the USGS about the particular parameter.
@@ -22,7 +24,7 @@ parameterData data frame with all information from the USGS about the particular
 }
 }
 \description{
-Imports data from NWIS about meaured parameter based on user-supplied parameter code.
+Imports data from NWIS about meaured parameter based on user-supplied parameter code or codes.
 This function gets the data from here: \url{http://nwis.waterdata.usgs.gov/nwis/pmcodes}
 }
 \examples{