In the aftermath of a mortgage closing, credit scores decline 15 points, though they do recover with time. The drop occurs because after a consumer takes out a mortgage, a large balance is added to his credit report, according to a survey from Lending Tree.

Credit scoring models consider a consumer’s total balance of money owed, and a large increase in outstanding debt drives scores lower. Also, the creation of a new credit line item also weighs on the score, though to a lower extent.

To be sure, a mortgage also increases the diversity of accounts in the credit file, which also boosts the score. As time passes, making on-time payments helps a borrower improve their credit score as they demonstrate they are managing their new mortgage account well. Eventually, the score returns to its pre-mortgage level, and often, surpasses it.

"A house is the biggest purchase most people make in their lifetime, with the accompanying mortgage being their largest financial transaction," said Tendayi Kapfidze, chief economist at LendingTree that. "Most people know they should work toward having the best possible credit score before applying for a mortgage, as an applicant's credit score can significantly affect the amount and cost of borrowing. But what happens to your credit score after you get a mortgage?" wasn’t necessarily clear.

Among the key findings of the report are the following:

• Scores fall for at least four months.On average, credit scores fell by 15 points and took 160 days, or just over five months, to reach their low points. Mortgages do not appear on credit reports immediately after closing. Typically, the mortgage lender starts reporting to the credit bureaus after the first payment and depending on the lender's reporting cycle, so it may take about 60 days after closing or even longer for it show up and start affecting a score. New Orleans homeowners saw their credit scores reach their lowest points in an average time of 133 days, while Milwaukee homebuyers' scores had the longest decline: 191 days.
• Recovery takes at least another five months.It took an average of an additional 161 days for scores to return to their prior levels. As borrowers make on-time payments, their credit scores start to recover. In Richmond, Va., homebuyers' credit scores rebounded fastest at 130 days, while the upward climb for homeowners in Austin, Texas, lasted 197 days.
• Eleven months later, scores recover and are poised to move higher.The average for the complete decline and recovery cycle was 11 months nationally. Richmond homebuyers saw their credit scores go through the cycle the fastest, nine months, while the dip and return of Milwaukee homebuyers' scores took the longest, 13 months.
• Tight range of score declines.The average score fell the most in Virginia Beach, Va., down 20 points, and the least in Minneapolis at just 11 points. Individual credit scores in the sample declined as much as 40 points.