Your tap water is faily high in SO4 and Bicarbonate. These might not be too desireable for a Helles/Pils.
Kaiser has some water recipes on his page. You will see that the water for Helles is soft and 0 alkalinity. Some more Ca provided by CaCL2 would help, shoot for 50 ppm or so.http://braukaiser.com/wiki/index.php?title=Various_water_recipes
Martin's "Bru'ngwater" program is very good, and will have a water profile for light beers like this.
Martin might say something later, so listen to him, as he knows water.
With any lager, the yeast, pitch rate, oxygenation, fermentation temps, lagering temp and time are what makes a good one, or a great one.
The easy way to do this would be to dilute the tap water with equal amounts of the distilled. Then add some CaCl2 to get he Ca back up to 50 ppm. The Bicarbonate will be a little high, and the sulfates will be a little high. You might want to have some acid on hand to adjust pH down, if you can measure the pH.