The level of NPAs represents an indicator of the potential for future credit losses. NPAs consist of non-accrual loans and leases and other real estate owned. Changes in the level of non-accrual loans and leases typically represent increases for loans and leases that reach a specified past due status, offset by reductions for loans and leases that are charged-off, paid down, sold, transferred to held for sale classification, transferred to other real estate owned or are no longer classified as non-accrual because they have returned to accrual status as a result of continued performance and an improvement in the borrower’s financial condition and loan repayment capabilities.
Total NPAs were $8.6 million as of September 30, 2021, a decrease of $0.5 million or 5% from December 31, 2020. The ratio of our NPAs to total loans and leases and other real estate owned was 0.07% as of both September 30, 2021 and December 31, 2020. During the nine months ended September 30, 2021, construction non-accrual loans decreased by $2.0 million, offset by increases in commercial real estate non-accrual loans of $0.7 million, residential mortgage non-accrual loans of $0.7 million and commercial and industrial non-accrual loans of $0.2 million.
As of September 30, 2021, commercial real estate non-accrual loans were $0.7 million, an increase of $0.7 million from December 31, 2020. This increase was due to the addition of a $0.9 million commercial real estate loan, partially offset by payments.
As of September 30, 2021, commercial and industrial non-accrual loans were $0.7 million, an increase of $0.2 million or 44% from December 31, 2020. This increase was primarily due to additions in commercial and industrial loans totaling $0.5 million, partially offset by payments and charge-offs.
As of September 30, 2021, construction non-accrual loans were nil, a decrease of $2.0 million from December 31, 2020. This decrease was primarily due to a $1.8 million transfer to loans held for sale and payments of $0.6 million, partially offset by an addition of $0.4 million.
The largest component of our NPAs continues to be residential mortgage loans. The level of these NPAs can remain elevated due to a lengthy judicial foreclosure process in Hawaii. As of September 30, 2021, residential mortgage non-accrual loans were $7.1 million, an increase of $0.7 million or 11% from December 31, 2020. This increase was primarily due to additions of residential mortgage non-accrual loans totaling $3.8 million, partially offset by returns to accrual status of $2.5 million and payments of $0.6 million. As of September 30, 2021, our residential mortgage non-accrual loans were comprised of 35 loans with a weighted average current LTV ratio of 45%.
Other real estate owned represents property acquired as the result of borrower defaults on loans. Other real estate owned is recorded at fair value, less estimated selling costs, at the time of foreclosure. On an ongoing basis, properties are appraised as required by market conditions and applicable regulations. As of both September 30, 2021 and December 31, 2020, there were no other real estate owned.
Loans and Leases Past Due 90 Days or More and Still Accruing Interest. Loans and leases in this category are 90 days or more past due, as to principal or interest, and are still accruing interest because they are well secured and in the process of collection.
Loans and leases past due 90 days or more and still accruing interest were $5.8 million as of September 30, 2021, a decrease of $5.4 million or 48% as compared to December 31, 2020. This decrease was primarily due to decreases in consumer loans of $1.9 million, commercial and industrial loans of $1.7 million, home equity lines of $0.9 million and commercial real estate loans of $0.9 million that were past due 90 days or more and still accruing interest.
Impaired Loans. A loan is impaired when, based on current information and events, it is probable that a creditor will be unable to collect all amounts due according to the contractual terms of the loan agreement. For a loan that has been modified in a TDR, the contractual terms of the loan agreement refers to the contractual terms specified by the original loan agreement, not the contractual terms specified by the modified loan agreement.