What should our HOA do when a neighboring developer wants to drain stormwater into our detention pond?

By OurHOA · General information · Revised October 19, 2026

How an HOA board should handle a developer's request to send stormwater into its detention pond: engineering review, a drainage agreement, cost sharing and permits.

Part of the HOA board handbook: vendors, projects and upkeep.

The short answer

Do not say yes in a hallway conversation, and do not sign anything the developer's engineer drafts until your own engineer has checked the numbers. A detention pond is sized for a set drainage area. Add a new subdivision's runoff and the pond fills faster, holds water longer, silts up sooner and may overtop onto your lots in a large storm. Those costs land on your owners for decades, while the developer leaves when the last house sells. A yes can still be the right answer. Sometimes the developer offers to enlarge the pond, rebuild a failing outlet or pay for the next dredge. The board's job is to turn the request into a written drainage agreement that protects capacity, puts a fair share of the upkeep on the new land, and gets every required permit change approved before any pipe connects. Rules vary by state, by city and by your own declaration and plat. This guide is education, not legal advice, and the agreement itself belongs with the association's attorney.

Find out what you own and what you already promised

Start with paper. Pull the recorded plat, the declaration, any drainage easements, the deed to the pond lot, and the as-built drawings and permit for the pond. The city engineering department or your developer's turnover binder usually has the drainage report that sized it. You are looking for three things. First, who owns the land under the pond, and whether the association has authority to grant rights over common area or needs an owner vote under your declaration. Second, whether the plat already shows a drainage easement in favor of the neighboring tract. Developers sometimes planned for this years ago, and if the right is already recorded, you are negotiating maintenance terms, not whether to say no. Third, what the permit says about who maintains the pond and how much water it may release. If you cannot find the drainage report, ask the city for it before the first meeting with the developer. You need the design storm, the drainage area and the allowed outflow rate to have any real conversation.

Hire your own engineer, paid for by the developer

The developer's civil engineer works for the developer. Ask for the full drainage study for the new project, then have a licensed engineer who answers to the board review it. Put the review cost on the developer in a short letter agreement before the work starts. Asking for a deposit against the review fee is reasonable, and a developer who refuses to pay for a review is telling you something. Your engineer should answer plain questions in writing. How much extra volume reaches the pond in the design storm? Does the outlet structure still hold the release rate the city requires? How much higher does the water rise in a 100-year storm, and does it reach any yard, fence or house pad? How much more sediment will the pond collect each year, and what does that do to the dredging schedule? Does the new runoff come in already treated, or does it bring construction silt? If the answers show the pond is too small, the honest options are a larger pond, on-site detention on the developer's land before the water reaches you, or no.

What state law says about runoff

Texas. Water Code section 11.086 bars anyone from diverting or impounding the natural flow of surface water in a way that damages another person's property by overflow, and lets the injured owner sue for damages and other relief. That protects your lots if the new project floods them, but a lawsuit after a flood is a poor substitute for a good agreement before construction. Florida. Stormwater systems are permitted under Chapter 373, Part IV of the statutes through an environmental resource permit. Rule 62-330.020(2)(j) of the Florida Administrative Code requires a permit for any modification of a previously permitted project, and Rule 62-330.315 treats a change that increases off-site discharge or reduces required detention as a major modification, reviewed like a new application. Under Rule 62-330.310, the association named as operation and maintenance entity stays responsible for permit compliance until the permit is formally transferred or modified. Do not let new pipes connect to your system without that modification approved. Colorado. Section 37-92-602(8) of the Colorado Revised Statutes protects certain stormwater detention facilities owned, operated or overseen by a government entity from water rights claims if they release at least 97 percent of the runoff from storms up to the five-year event within 72 hours, and 99 percent of larger storms within 120 hours. Facilities built after August 5, 2015 must send notice to the State Engineer's notification list before they operate. If a redesign changes how long your pond holds water, ask your engineer and the city whether the pond still meets those limits. Federally, a construction site that disturbs one acre or more needs Clean Water Act stormwater permit coverage, and so does a smaller site that is part of a larger plan of development. Ask the developer for a copy of their coverage and the erosion control plan.

What the drainage agreement should cover

Have the association's attorney draft or mark up the agreement, and record it so it binds whoever owns the new tract later. At a minimum it should cover: Capacity. The maximum drainage area, the design storm and the release rates, tied to the approved engineering plans. Any later increase needs a new written approval. Improvements. Who pays to enlarge the pond, rebuild the outlet or add an inlet, the standards for the work, and the association's right to inspect before acceptance. Upkeep share. A formula for mowing, inspections, outlet repair and dredging. Splitting by the acres that drain to the pond is common and easy to defend. Sediment during construction. The developer cleans out silt that reaches the pond until the new phase is built out and stabilized, at its own cost. Insurance and indemnity. The developer and its contractors name the association as additional insured during construction and indemnify it for damage from their work. Successors. The duty to pay passes to the new subdivision's own HOA when it takes over, with a recorded covenant so the payment does not disappear at turnover.

A sample timeline and motion

Week 1: the developer's request arrives. The president acknowledges it in writing and says the board will respond after an engineering review at the developer's expense. Weeks 2 to 4: pull the plat, easements, permits and drainage report. Sign the review-cost letter. Engage the engineer. Weeks 5 to 8: the engineer's written findings come back. The board meets with the developer to negotiate improvements and cost share. Weeks 9 to 12: the attorney drafts the agreement. Tell owners what is proposed, with a map, at an open meeting. Hold an owner vote if the declaration requires one for granting rights over common area. After signing: the developer obtains city approval and, in Florida, the permit modification. No connection until both are in hand. Sample motion: "I move that the board approve the drainage agreement with [developer] dated [date], subject to the association's engineer confirming in writing that the final construction plans match the reviewed design, and that the agreement be recorded before any connection to the association's pond."

Mistakes boards make

Agreeing to a handshake deal. A friendly project manager moves on, and the next owner of the tract has never heard of the promise. Accepting a flat payment instead of an ongoing share. A one-time check looks generous until the first dredging bid arrives, and a pond needs dredging more than once in its life. Skipping the sediment terms. A new subdivision under construction can put more silt in a pond in two years than your own homes add in twenty. Forgetting the permit. In Florida, the association can stay on the hook for a system someone else changed. Not telling owners. Neighbors notice a new pipe in the pond bank. Explain the deal before construction, and point to the engineer's findings. Our guides on setting up a retention pond maintenance schedule and setting up a cost-sharing agreement with a neighboring HOA cover the upkeep side once the new flow arrives.

Sources

These guides are general education for HOA boards and residents, not legal, tax, or financial advice. Rules vary by state and by your community's governing documents - check with a professional for your situation.

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