Sales fell in the Northeast (-23.8 percent to 32 thousand), the West (-21.3 percent to 144 thousand) and the South (-4.1 percent to 326 thousand) but rose in the Midwest (6.2 percent to 69 thousand).
The median sales price of new houses sold was $313,700, above $295,000 a year earlier. The average sales price was $371,200, also higher than $355,000 in July of 2016.
The stock of new houses for sale went up to 276 thousand from 272 thousand in June, hitting the highest level since June 2009. This represents a supply of 5.8 months at the current sales rate.
Year-on-year, new home sales shrank 8.9 percent.
Figures for June were revised up to 630 thousand from an initial estimate of 610 thousand. The May figure was also revised to 618 thousand from 605 thousand and the April reading to 590 thousand from 577 thousand.