(a) If the landlord of a rental unit fails to repair, maintain or keep in a sanitary condition the leased premises or perform in any other manner required by statute, code or ordinance, or as agreed to in the a rental agreement; and, if after being notified in writing by the tenant to do so, the landlord:

(1) Fails to remedy such failure within 30 days from the receipt of the notice; or

(2) Fails to initiate reasonable corrective measures where appropriate, including, but not limited to, the obtaining of an estimate of the prospective costs of the correction, within 10 days from the receipt of the notice;

Then the tenant may immediately do or have done the necessary work in a professional manner. After the work is done, the tenant may deduct from the rent a reasonable sum, not exceeding $200, or 1/2 of 1 month’s rent, whichever is less, for the expenditures by submitting to the landlord copies of those receipts covering at least the sum deducted.

(b) In no event may a tenant repair or cause anything to be repaired at the landlord’s expense when the condition complained of was caused by the want of due care by the tenant, a member of the tenant’s family or another person on the premises with the tenant’s consent.

(c) A tenant who is otherwise delinquent in the payment of rent may not take advantage of the remedies provided in this section.

(d) The tenant is liable for any damage to persons or property where such damage was caused by the tenant or by someone authorized by the tenant in making said repairs.

70 Del. Laws, c. 513, § 2.