HomebrewandBeer.com forum

My first brew I made recently I added too much water,the beer turned out ok ,easy to drink slightly lacking in carbonation but still with a kick,I am looking for the affect of adding too much water and how much is too much.

There's no simple answer to your question.
It all depends on the recipe you are making, and the style of beer it fits into.
Every beer style has a range of Starting Gravities (SG), and if you dilute your brew to drop below the lower level of SG for the style, you have added too much water. You'll end up with an insipid tasteless beer.
It's a bit like trying to make a cordial drink with only 2 or 3 drops of cordial and adding a full glass of water. You might have a glass of liquid with colour in it, but it will taste pretty horrible.
If you want to brew a larger batch, increase the ingredients in your recipe.