This creates a huge amount of drag, so much in fact that working on lifting your body position higher should be your number one priority to improve your swimming.
For comparison, here is how high double Olympic Gold Medallist Rebecca Adlington's sits in the water:
Most people with low legs are aware it's a problem for them but if you are not sure, you can tell from how much easier you feel swimming with a pull-buoy or in a wetsuit. It's not uncommon for someone with low legs to be 5, 10 or even 20 seconds faster per 100m using a large pull-buoy or wetsuit!
If you suffer from sinky legs, you might never get as high in the water as Rebecca but so large is the drag created that even small improvements will give you a big step forwards with your swimming.
Another Reason You Might Sit Low In The Water