The Horry County Stormwater Department maintains drainage systems in Horry County. They also conduct mosquito spraying and issue stormwater permits.


Citizens who have been notified of their eligibility to receive a Stormwater Refund may begin that process by completing the Stormwater Refund form below. Using this form you may also opt to donate your refund to the Horry County Animal Care Center.

Stormwater Refund

Stormwater Nav Bar

To report a drainage or water quality problem, please call the hotline: 843-381-8000.

Upcoming Workshop

Know Your Neighborhood Stormwater System
September 21, 2022
Carolina Forest Recreation Center

Our workshop is a neighborhood guide to knowing how a stormwater system, such as a retention pond, is a tool for managing the runoff that results from rainfall. These systems need to be maintained in order to keep them functioning correctly to help flooding and water quality concerns.

Please fill out the registration form to reserve your spot.

Strategic Plan

In 2004, Horry County began a strategic planning process that yielded a Council-approved plan, which was updated during 2007-2008. The plan was developed by staff and its citizen advisory committee. The plan is intended to:

  • Ensure that the stormwater management program is appropriately aligned with the expectations of County Council and the community.
  • Establish a unified, articulated plan that can be communicated to employees that clearly convey program priority and direction
  • Ensure that limited resources are appropriately allocated to achieve the objectives of County Council and Executive Management.
Periodically, the strategic plan is updated as needed.

Major Initiatives


A primary activity and common citizen request is to maintain or improve public drainage and associated infrastructure, including catch basins, storm sewer pipes, major ditches, and regional ponds. Significant personnel and equipment are dedicated to this initiative.

Read more

A common citizen concern and primary role of the Department is drainage maintenance and improvements. The County holds many public drainage easements for the purpose of maintaining storm drainage infrastructure. Easements are designed to allow personnel and equipment to access, repair or maintain infrastructure. The Department discourages any encroachments into any drainage easements (public or private), as this may limit the Department’s ability to properly maintain stormwater infrastructure, potentially result in system failure.

Catch basins in public easements are inspected and cleaned, typically by a vacuum truck. Maintenance is routinely done on a cycle, but can also be done as needed so that the storm sewer system operates smoothly. Drainage ditches in public easements are inspected and cleaned as needed with a hand crew or mechanized equipment. Like catch basins and pipes, the drainage ditches are routinely cleaned on a cycle, but can also be done as needed so the conveyance operates smoothly. Some ditches may be maintained using equipment, while others may require the use of hand crews. In some cases, new drainage ditches may be constructed. There are several watershed areas in the County that are exclusively maintained by the Department as part of a special tax district.

Note that the Department has limitations in where it can operate. Public funds may not be used for private benefit. Also, federal and state environmental rules, primarily wetland regulations, limit the County’s ability to work in wet and swampy areas.


A stormwater permitting program is another primary role of the Stormwater Department. New development can impact downstream flooding and water quality. The permitting program aims to reduce impacts of development by setting and enforcing standards for the quantity and quality of stormwater runoff from development sites.

Construction Site Stormwater Runoff Control - Minimum Control Measure #4

MCM 4 is Construction Site Stormwater Runoff Control. Construction sites are a significant contributor of sediment pollution that impacts rivers, lakes and estuaries. Sediment in waterbodies from construction sites can reduce the amount of sunlight reaching aquatic plants, clog fish gills, smother aquatic habitat and spawning areas, and impede navigation.

SMS4s are required to develop a program to reduce pollutants in stormwater runoff to the MS4 for construction sites disturbing one or more acres. Horry County’s program includes: an ordinance [link] and design manual [link] with requirements for stormwater management and erosion and sediment control best management practices at construction sites; construction site plan review; and inspections and enforcement procedures for construction sites.


To achieve environmental compliance, a primary activity is to educate citizens and businesses about how they can help to protect our waterways from stormwater runoff. To achieve this, the county has partnered with other local governments and education providers to form a Stormwater Education Consortium.

Public Education and Outreach - Minimum Control Measure #1

The first MCM is Public Education and Outreach. Stormwater runoff is generated throughout the landscape – roads, yards, driveways, roofs and parking lots. Therefore, efforts to control stormwater pollution must consider individual, household, and public behaviors and activities that can generate pollution from these surfaces.

SMS4s are required to educate their community on the pollution potential of common activities, and increase awareness of the direct links between land activities, rainfall-runoff, storm drains, and their local water resources. SMS4s are also required to give the public clear guidance on specific actions that they can take to reduce their stormwater pollution-potential.

In Horry County and the Grand Strand region, public education and outreach is coordinated through the Coastal Waccamaw Stormwater Education Consortium.

Mosquito Control

Due to its connection to water, mosquito control is a responsibility of the Stormwater Department. The County expends significant resources to control mosquitoes by aerial sprayings, truck and ATV treatments, and larvacide applications. Strict procedures govern when and how treatments are applied. Citizens with health concerns or beekeeping operations can request exclusions. To request a no-spray zone, please fill out this form.

Mosquito-borne Diseases

For specific information about mosquito-borne illness, please visit the Centers for Disease Control. For specifics about the Zika virus, please visit this CDC page. For more information on the Zika virus and how to protect yourself and your family, call the SC Department of Health and Environmental Control's toll free Care Line at 1-800-868-0404.

Common mosquito-borne diseases in the U.S. include West Nile virus, Chikungunya virus, eastern equine encephalitis, St. Louis encephalitis, LaCrosse encephalitis, and dog heartworm. Mosquitoes do NOT transmit HIV/AIDS. For more detailed information, visit the SC Dept. of Health and Environmental Control's Mosquito website.

Mosquito-borne diseases can affect pets and domestic animals. PLEASE ensure that your pets and domestic animals are vaccinated or treated against common diseases, such as dog heartworm and eastern equine encephalitis. Once an animal is infected, it may be difficult or impossible to treat and the effects may be life-threatening.

Horry County Mosquito Control uses insect collection traps to monitor mosquitoes and mosquito-borne diseases. Mosquito Control uses these surveillance devices to identify the location and extent of mosquito-related problems. PLEASE DO NOT DISTURB our surveillance traps. These traps provide critical public health information.

West Nile virus (WNV) can infect birds which can then act as transmitters of disease. When a mosquito draws blood from an infected bird, it carries WNV and may transmit the disease to other animals, including humans. Horry County encourages its citizens and visitors to report dead birds by calling 843-381-8000. Specifically, SC Dept. of Health and Environmental Control (SCDHEC) will evaluate dead American crows, fish crows, blue jays, house finches, and house sparrows from March 15-November 30 to determine whether they are carriers of WNV. SCDHEC will consider evaluating a dead bird if:

  • the bird is "freshly dead" (within 24 hours)
  • the bird is intact (no physical trauma)
  • no maggots (fly larvae) are present
  • the body is not stiff
  • the bird does not have sunken eyes
  • the bird appears dead by natural causes
If you encounter a dead bird, please do not handle the body with your bare hands.


Mosquito Control in Your Backyard

Mosquitoes are a public health concern, as they can transmit diseases to humans, their pets, and their livestock. Protect yourself! Put a barrier between you and mosquitoes, such as window screens (keep in good repair) and mosquito-proof clothing and bedding. If you're going to be outdoors, use insect repellent and avoid common hiding places such as high grass and dense underbrush. Avoid wearing perfume and scented products and wear light-colored clothing.

All mosquitoes need water to pass their early life stages. Only female mosquitoes bite, as they need a blood meal to produce eggs. Mosquitoes lay their eggs in water-filled containers, permanent standing water, and floodplains that are occasionally inundated by floodwaters. In general, water must be standing for 7-10 days to produce mosquitoes.

The most common breeding sites for mosquitoes near homes is water-filled containers. Mosquito larvae do not survive in flowing water and natural predators limit mosquito breeding in ponds, lakes, and even ditches. Examples of common containers that produce mosquitoes around homes are: play or ornamental pools, buckets, boats, bags and tarps, birdbaths, clogged gutters, and yard drains. For example, recently in our region, a plastic grocery bag harbored 3,000 mosquito larvae.

To eliminate breeding sites around your home or place of business, look for any place that standing water can collect. Empty water-filled containers regularly, such as pet dishes or birdbaths. Turn containers upside down or remove them from exposure to rain.

Beekeepers and Organic Farmers

Beekeepers and organic farmers may wish to avoid the insecticides used with adult mosquito control. Problems may arise if these insecticides come into contact with honey bees, as honey bees are susceptible to many insecticides. In fact, pesticides are a major cause of honey bee deaths. Horry County has chosen to grant courtesy no-spray requests to organic farmers as well by not fogging within approximately 100 ft of the approved location. To let us know about your honey bee population or organic farm so we may help to protect it during our mosquito spray program, please fill out and submit the form at the bottom of this page. The county will require a copy of your licensing and you will be given consideration by the County to the extent feasible and practicable. Note that it takes at least 24 hours to update the online map in order to honor an approved no-spray request.

Below is a map of registered bee colony locations, which will be avoided during spray operations.

Click the plus symbol to zoom in. You can click and drag the map to focus on a particular location.
View Larger Map

Citizens with Special Needs

Some citizens do not wish to have adult mosquito control. Individuals with special medical problems possibly attributed to insecticide exposure can obtain a physician’s written opinion acknowledging pesticide sensitivity, and such people will be given consideration by Horry County to the extent feasible and practicable. Most people having health-related concerns over insecticide exposures can satisfactorily minimize their concerns by paying attention to the fogging schedule and following common sense measures such as temporarily leaving the fogging area; closing doors, windows, and vents in the house; etc. However, given the safety of the EPA-registered insecticides used and how the products are applied with extremely minimal human health risk, the vast majority will not need to take special precautions.

Chemical and Application Information

Mosquito Control is regulated by Federal, State and local laws. These laws determine exactly when and how Horry County controls its mosquito population. Horry County Mosquito Control is under the auspices of the Storm Water Department. The program is funded by the stormwater management utility fee.

Mosquito Control strives to investigate all citizen inquiries within 24 hours.  This service begins with a site inspection of the citizen's yard, of nearby wooded areas, drainage ditches, swamps, retention ponds and any known local breeding sites. 

Horry County Mosquito Control uses an Integrated Mosquito Management (IMM) philosophy when controlling the mosquito population. IMM combines a variety of mechanical (eliminating the water in which the mosquitoes need to breed) and chemical control techniques (using adulticides to control adult mosquito populations and larvacides to control larvae before they hatch) to provide a more effective approach for the control of mosquitoes.

Manual Treatment

The development of the solid formulations or briquettes have provided opportunities for long term mosquito larval control in their breeding aquatic habitats. These larvacide treatments typically range from 30-180 days of mosquito development and emergence prevention at potential breeding sites. They are used in ponds and catch basins most effectively. The Division also operates four ultra-low volume (ULV) fogging machines, which allow the treatment of populated areas without undue hazard to local residents and the environment. These ground units are used for control in parks, summer camps, and other outdoor areas where people congregate.

Truck Mounted Treatment

Mosquito control agencies use truck-mounted fogging units to apply insecticides as an ultra-low-volume (ULV) spray. ULV spray units dispense very fine aerosol droplets (fog) that stay aloft and kill mosquitoes on contact. The amount of insecticide sprayed by ULV units is small compared to the area treated, usually about 3 to 5 ounces per acre, which minimizes exposure and risks to people and the environment. Some communities have thermal foggers that use an oil carrier that is heated to disperse the pesticide in a dense smoke-like fog. The best time to kill adult mosquitoes by fogging is at dusk, when they are most active and looking for food (mosquitoes feed on human or animal blood). The aerosol fog primarily targets flying mosquitoes, which is why the timing of the spray is critical.

Aerial Treatment

The County contracts with a licensed aerial spraying contractor, who can treat large inaccessible areas quickly and effectively, thereby reducing the economic and health threat posed by mosquito infestations. Click for aerial spray grid.

Spray Map

Aerial spraying will occur in the Bucksport area on Thursday, September 22 and Pitch area on Friday, September 23, weather permitting.

Mosquito Spray Update:

When aerial spraying is scheduled, the interactive map to the left shows the target spray areas outlined in red. Aerial spraying typically starts around dusk, and can continue well into the evening, weather permitting.
Ground spraying by truck is ongoing, weather permitting. Ground spraying occurs in the evening Monday through Thursday, as needed. Truck spraying will typically start around dusk, and usually ends around 11:00 pm.
View Larger Map

Environmental Compliance

The state of South Carolina has designated the county as a qualifying local program under the municipal stormwater program of the National Pollutant Discharge Elimination System of the federal Clean Water Act. As such, the county is responsible for ensuring compliance with environmental regulations that are designed to protect the nation’s waterways.

Public Involvement and Participation - Minimum Control Measure #2

MCM 2 is Public Involvement and Participation. Besides following public notice requirements, SMS4s must offer opportunities for the public to participate in stormwater program development and implementation, such as the Stormwater Advisory Board and ad hoc committees and meetings. Public involvement includes opportunities for direct action, such as storm drain marking, stream clean-ups, or volunteer water quality monitoring. For more information, click here.

Illicit Discharge Detection and Elimination - Minimum Control Measure #3

MCM 3 is Illicit Discharge Detection and Elimination. Illicit discharges are discharges into the storm sewer system (e.g. storm drains, ditches, ponds) that are not entirely composed of stormwater. SMS4s are required to screen outfall pipes for illicit discharges, respond to reports of illegal discharges, and map the storm sewer system to be able to track the sources of illicit discharges. SMS4s must address illegal discharges because stormwater runoff is not treated at a treatment plant before discharging into our waterways.

Examples of illegal discharges include: chemical spills, failing septic systems, overflowing grease traps, leaking trash dumpsters, washing paint or construction waste down the storm drain, and depositing pet waste into storm drains or ditches. Examples of exceptions are firefighting activities or water utility line flushing. For more information, click here.

To report hazardous chemical spills, oil spills, or fish kills, contact SC DHEC Emergency Response at 1-888-481-0125.

Post-construction Stormwater Management in New Development and Redevelopment - Minimum Control Measure #5

MCM 5 is Post-construction Stormwater Management in New Development and Redevelopment. Development results in increased impervious surfaces from roads, rooftops, parking lots, and sidewalks that increases stormwater rate and volume and potentially degrades water quality in local waterways.

SMS4s must address post-construction stormwater runoff from new development and redevelopments that disturb one or more acres. This is done by requiring developments to mitigate stormwater impacts by using practices to treat, store, and infiltrate runoff onsite before it can affect water bodies downstream. This is commonly achieved by using stormwater retention ponds.

In recent years, Horry County has emphasized the use of smaller-scale low impact development practices dispersed throughout a site to achieve reduced flows and improved water quality. Long-term operation and maintenance of these practices is critical to their effectiveness, which is typically the responsibility of the property owner or property owners association. For more information, click here.

Pollution Prevention and Good Housekeeping for Municipal Operations - Minimum Control Measure #6

MCM 6 is Pollution Prevention and Good Housekeeping for Municipal Operations. Local governments maintain facilities and conduct activities that have pollution potential, including storage yards, waste transfer stations, road repairs, fleet maintenance, landscaping and building maintenance.

Staff training is conducted and standard operating procedures are developed to minimize impacts from these activities. Local governments also conduct activities that remove pollutants, such as parking lot and street sweeping and storm drain system cleaning. For more information, click here.

Utility Fee

In 2000, the County established its first stormwater ordinance and an associated utility fee to pay for capital improvements and major initiatives. The utility fee is based upon the assumption that every property generates some stormwater runoff, dependent upon the amount of impervious area, and that stormwater runoff eventually reaches public drainage and public waterways. Therefore, every property owner contributes to stormwater runoff and should contribute to operation and maintenance of public infrastructure and required stormwater programs.

Read more

Stormwater utility fees are paid by each property owner in the unincorporated areas of Horry County. Similar to other service utilities, like electricity and water, the stormwater fee is based on how much your property uses the drainage system. Fees are based on the gross area and intensity of development of each property (i.e. impervious surfaces), which affect how much stormwater runs off the property and ultimately into the public drainage system. Impervious surfaces prevent or impede natural infiltration of stormwater into the soil and lead to concentrated stormwater runoff. Common impervious surfaces include rooftops, sidewalks, walkways, patio areas, driveways, parking lots, storage area, compacted gravel and soil surfaces, awnings and other fabric or plastic coverings.

Stormwater utility fees appear on real property tax bills and are collected by the County Treasurer with your property taxes. Billing is done by Equivalent Residential Units or ERUs that represent the average gross area and development intensity factor for a typical single family residential property. Single-family homes, townhomes and condominiums are charged a flat fee. Non-residential properties are charged according to a formula that accounts for each property's gross area and development intensity.

Examples of fees for common property types appear in the table below:

Gross Area
ERUs Monthly Fee
per ERU
Annual Fee
20,000 sq ft 0.25 1 $7.45/ERU $7.45/
Commercial 95,832 sq ft 0.40 7.67 $7.45/ERU $57.14/
130,680 sq ft 0.95 24.82 $7.45/ERU $184.98/
Outlet Mall 936,540 sq ft 0.95 177.94 $7.45/ERU $1,325.67/
Church 204,732 sq ft 0.20 8.19 $7.45/ERU $61.01/
Large Tract
with Marsh
6,629,832 sq ft
3,220,000 sq ft
credit for marsh
12 acres)

$7.45/ERU $12.12/

The History of Drainage and Land Management in Horry County


On March 10, 1731, surveyors were commissioned to lay out the township called Kingston on the west bank of the Waccamaw River. About three years later a town, also called Kingston, was planned near the center of the township, which was opened to inhabitants of the province for settlement in 1735, by order of the Lieutenant Governor and council. This area was included in the Georgetown District, one of Seven districts into which the state was divided in 1768. In 1785, the Georgetown District was further divided into four counties, one of them Kingston with the same boundaries as the present Horry County. The name was not changed, however, until 1801 when the citizens of Kingston County, Georgetown District, petitioned the General Assembly to make the county into a district with the name Horry; the name honored Peter Horry, Brigadier General of the militia that encompassed Kingston. They further petitioned for the name of the town of Kingston to be changed to Hugerborough, but it was named Conwayborough instead, which became the county seat. It was not until 1868 that the name "Horry District" was changed to the present name of Horry County.

Since the first settlement was made in the Kingston Township (now Horry County) in March 1731, the existing problem of imperfect internal and surface drainage has retarded the growth and development of this area in South Carolina.The higher areas of land were used by the first settlers for homesteads and for small fields to produce food crops. Low, wet lands were left in their natural state. As settlements grew and more land was needed for farming operations, it was necessary to install some type of drainage system on individual farms. These drainage systems were inadequate and only partially met the drainage needs. The lack of knowledge of drainage systems and the availability of only hand tools retarded the design and installation of complete systems.

With the increase in land use and particularly with the advent of modern construction machinery such as the bulldozer, dragline, and backhoe, it became relatively easy to excavate larger canals and outlet ditches needed for adequate drainage. Even with the new machines, much of the drainage work installed has been the result of expediency incident to population growth and did not follow a well-developed plan of action. Improving the quality and quantity of agricultural crops and providing well drained areas for home sites are essential to perpetuate economic growth of a community; providing additional drainage is necessary as a first step toward enhancing the environment and increasing income for its people.

Excerpt from History of "Horry County" by Laura Quattlebaum (unpublished)

Contact Us

To ensure your question/concern is routed to the proper team member, please click here for district information.

Department Well

Department Head
Thom Roth
Phone: (843) 915-5160
Fax: (843) 365-2208
Mailing Address
4401 Privetts Road
Conway, SC 29526
Physical Address
4401 Privetts Road
Conway, SC 29526
Office Hours
8:00 AM - 5:00 PM
Monday through Friday

Drainage Hotline

To create a service request or report a mosquito problem, click here

To report a drainage or water quality problem, please call the hotline: 843-381-8000.