Q: Can I take legal action to mandate a drain installation and seek compensation for parking lot damage?

A: Based on property law principles applicable to your situation, you may have viable legal claims against the adjacent parking lot owner under theories of nuisance, trespass, and negligence. When a neighboring property causes water to flow onto your land in an unnatural manner or at increased volume, this typically constitutes a private nuisance that courts can remedy through both injunctive relief and monetary damages. The physical damage to your retaining wall from the wheel stops likely constitutes trespass, providing a separate cause of action.

Regarding your procedural questions, the appropriate court for your claims depends on the monetary jurisdiction limits in your state. While magistrate courts (sometimes called small claims) are limited in their jurisdiction—typically to amounts between $5,000-$15,000 depending on the state—your $40-50K damage estimate would likely exceed this threshold, requiring filing in a higher court such as Superior or Circuit Court. Most jurisdictions would allow you to combine your request for injunctive relief (mandating drain installation) with your claim for monetary damages in a single lawsuit, which is procedurally more efficient than filing separate actions.

I recommend taking several preparatory steps before proceeding. First, compile all documentation, including the engineer's report, correspondence with the lot owner, photographs of damage, repair estimates, and any communications with city officials. Second, have your engineer prepare a specific remediation plan detailing the drainage solutions needed. Third, send a final demand letter to the property owner outlining your claims, proposed solutions, and intention to file suit if not resolved. Given the technical nature of the drainage issues, Historic District considerations, and significant monetary damages involved, consulting with an attorney who handles property disputes would be advisable to ensure your claims are properly structured and presented to maximize likelihood of success.