For a 19 L (5 gal) batch, going from 1.070 to a 1.060 target takes 3.17 L of water, bringing the total volume to 22.17 L. Reproduce this exact result, or swap in your own starting volume if it isn't exactly 19 L — the ratio between old and new gravity stays the same regardless of your specific volume, but the litres of water needed scales with it.
The arithmetic, so you can check it yourself
Dilution is worked in gravity points ((SG - 1) x 1000), because gravity points are additive across a diluted volume in a way specific gravity itself isn't. 1.070 is 70 points; 1.060 is 60 points. The total points in the batch don't change when you add plain water — they just spread across more volume — so:
finalVolume = currentVolume x currentPoints / targetPoints = 19 x 70 / 60 = 22.17 L
Subtract the starting 19 L, and the water to add is 3.17 L. This is the same method behind every dilution result on this site, worked with your specific numbers instead of a formula in the abstract.
If your starting volume isn't 19 L
The ratio (70/60, or roughly 1.167) applies regardless of your actual starting volume — a 23 L batch going from 1.070 to 1.060 needs the same proportional water addition, just scaled up: 23 x 1.167 - 23 ≈ 3.83 L. Rather than doing that scaling by hand, enter your actual starting volume directly and let the calculator handle it precisely.
Why you might be looking at exactly this pair
1.070 to 1.060 is a common correction when a boil ran a bit long, or pre-boil volume came in short, concentrating the wort by roughly 10 gravity points beyond what the recipe intended — a completely normal, easily-corrected deviation rather than a sign anything went seriously wrong. See how to dilute a too-strong wort for the fuller picture of when this correction is the right move versus when blending with a second batch serves you better instead — see dilution vs. blending: when to use which for that distinction in more depth.
One caution before you pour
Add the water in stages if you're not fully confident in your volume measurement, checking gravity again after each addition — diluting past your target is easy to do and there's no clean way to reverse it with plain water afterward, only by blending in something stronger.