diff --git a/R/constructNWISURL.r b/R/constructNWISURL.r
index 19a9ba67ea73bf32334d322dad160270ef3d7555..dfac1d29c71a6fcc6cd60bde29325d740a3817ca 100644
--- a/R/constructNWISURL.r
+++ b/R/constructNWISURL.r
@@ -45,7 +45,7 @@ constructNWISURL <- function(siteNumber,parameterCd="00060",startDate="",endDate
 
   service <- match.arg(service, c("dv","uv","iv","qw","gwlevels","rating","peak","meas"))
   
-  if(any(!is.na(parameterCd))){
+  if(any(!is.na(parameterCd) & parameterCd != "all")){
     pcodeCheck <- all(nchar(parameterCd) == 5) & all(!is.na(suppressWarnings(as.numeric(parameterCd))))
     
     if(!pcodeCheck){