CREATE TABLE table_30090 ("No. in series" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "U.S. viewers  ( millions ) " TEXT)

What episode number of the series is 'open water'?
SELECT "No. in series" FROM table_30090 WHERE "Title" = 'Open Water'
SELECT "No. in series" FROM "table_30090" WHERE "Title" = 'Open Water'