§ 4.1. Wastewater Infrastructure

Wastewater disposal is an important consideration in the planning process. As population increases, the need for additional central sewer capacities increases, particularly in areas not suitable for septic tanks, for non-residential projects or for residential projects desiring greater densities. Wastewater includes water from the kitchen and bathroom sinks, toilets, dishwashers, clothes washers, and bathtubs and showers.

Each day, every person within Santa Rosa County produces an average of approximately 90 gallons of wastewater. The final destination may be either an on-site treatment disposal system (usually a septic tank) or a regional treatment plant, which may be located many miles from the structure where wastewater is generated.

4.1.1 Septic Tank Systems

Septic tank or onsite sewage disposal systems are generally small and designed to serve one or a limited number of land uses. Despite expansion of the wastewater collection network, many residents within the unincorporated portion of the County do not have access to wastewater treatment facilities or package treatment plants. For these land uses, wastewater treatment and disposal is provided by individual septic systems. Septic tank systems provide on-site wastewater treatment for both residential and small-scale commercial developments. Residential septic tanks usually range in capacity from 900 to 1,000 gallons. Generally, commercial septic tanks have a larger capacity.

Septic tanks are a potentially important source of fecal coliform pollution in urban watersheds. When properly installed, most of the coliform from septic tanks should be removed within 50 meters of the drainage field (Minnesota Pollution Control Agency 1999). However, the physical properties of an aquifer, such as thickness, sediment type (sand, silt, and clay), and location play a large part in determining whether contaminants from the land surface will reach the ground water (USGS 2010). The risk of contamination is greater for unconfined (water table) aquifers than for confined aquifers because they usually are nearer to the land surface and lack an overlying confining layer to impede the movement of contaminants (USGS 2010).

Sediment type (sand, silt, and clay) also determines the risk of contamination in a particular watershed. According to the USGS (2010), "Porosity, which is the proportion of a volume of rock or soil that consists of open spaces, tells us how much water rock or soil can retain. Permeability is a measure of how easily water can travel through porous soil or bedrock. Soil and loose sediments, such as sand and gravel, are porous and permeable. They can hold a lot of water, and it flows easily through them. Although clay and shale are porous and can hold a lot of water, the pores in these fine-grained materials are so small that water flows very slowly through them. Clay has a low permeability."

Also, the risk of contamination is increased for areas with a relatively high ground water table. The drain field can be flooded during the rainy season, resulting in ponding, and coliform bacteria can pollute the surface water through stormwater runoff. Additionally, in these circumstances, a high water table can result in coliform bacteria pollution reaching the receiving waters through baseflow.

Septic tanks may also cause coliform pollution when they are built too close to irrigation wells. Any well that is installed in the surficial aquifer system will cause a drawdown. If the septic tank system is built too close to the well (e.g., less than 75 feet), the septic tank discharge will be within the cone of influence of the well. As a result, septic tank effluent may enter the well, and once the polluted water is used to irrigate lawns, coliform bacteria may reach the land surface and wash into surface waters through stormwater runoff.

The following Map 4-1 indicates areas of the County where soil conditions are present that present potential environmental problems with the use of onsite septic tank systems. This map includes the Planning areas, centralizes sewer is available within the Pace, Milton, East Milton and South End (including Navarre Beach) Planning Areas. Centralized sewer is generally not available within the Rural North Planning Area or most of Garcon Point.

Beginning in 1985, Santa Rosa County's Health Department began using a computer-aided database to track records for new septic tank systems, as well as repairs on existing systems. This database is used to track information such as permit number, location, soil type and system type (i.e., mound or standard). The number of systems that have been installed annually from 1990-2014 is graphed below ( Figure 4-1 ).

Figure 4-1: Number of New Septic Tanks Installed within Santa Rosa County by Year 1990—2014

Source: Santa Rosa County Health Department, Division of Environmental Health

From 2008 until today, the installation of new septic tanks has leveled off around at around 300 new systems being installed in the County annually. In the State of Florida approximately one-third of the population uses on-site systems or septic tanks. In Santa Rosa County approximately 50% of existing single family homes use on-site systems. Permits for septic tank systems and other onsite sewage treatment and disposal systems are issued by the Environmental Health Section of the Florida Department of Health's County office. Standards for septic tank systems and other onsite sewage treatment and disposal systems are found in 381.0065, Florida Statutes (F.S.) and Chapter 64E-6, F.A.C.

The County does discourage the use of septic tanks in areas where it is feasible to connect to a central system by requiring new platted residential subdivisions to connect to central sewer when such service is available within ½ mile of the new development. Individual residential homes requiring building permits are also required to connect to a centralized system if such system is available (basically located in front of house).

Map 4-1 Suitability for Septic Tank Absorption Fields Based on Table 10 - Soil Survey of Santa Rosa County

4.1.2 Centralized Wastewater Treatment Facilities

Within Santa Rosa County (including the unincorporated areas and municipalities of the County) there are six public wastewater treatment facilities (WWTFs) serving generalized development. Santa Rosa County owns and operates one public WWTF at Navarre Beach, the City of Milton operates two WWTFs and plans are in the works for a third, the Town of Jay owns one WWTF, Holley Navarre Water System owns one WWTF, Pace Water System Inc., operates one WWTF, and the City of Gulf Breeze owns one WWTF. Completing the list of public facilities, the Department of Defense and the Department of Corrections each own one WWTF respectively. Map 4-2 depicts the sewer service areas for the domestic systems operating within the County.

4.1.2.1 Sanitary Sewer Capacity Analysis (2014)

The annual Utilities Operational Status Report is hereby incorporated by reference and includes an analysis of these centralized facilities. Summary excerpts from this report (2014 data) are included below.

Rule 17-600.405, F.A.C., ensures that wastewater permittees conduct timely planning, design, and construction of wastewater facilities necessary to provide the proper treatment and reuse or disposal of wastewater and residuals. This rule requires the wastewater utilities in Santa Rosa County to routinely compare flows being treated with the permitted capacities. When the three-month average daily flow exceeds 50% of the permitted capacity, the utility must submit an initial capacity analysis report to the DEP District Office. Depending on the results, the utility may be required to submit updated capacity analysis reports or begin planning, design and construction of additional capacity.

Existing residential development within the Santa Rosa County sewer franchise areas is currently utilizing centralized sewer ranging between 36 to 100%, depending on franchise area, and the remaining existing development is utilizing septic tanks or onsite systems (See Table 4-1 ). In the Pace Water Systems franchise and the Holley Navarre franchise areas only around 36% and 51% of the single family homes are connected respectively. Within Town of Jay franchise area close to 100% of the residential structures are connected. Similarly, there are no on-site septic systems on Navarre Beach with 100% of the residential units connected to the centralized County operated system. There are approximately 40,000 residential onsite systems (septic tanks) in the County, with about 50% of the single family homes in the County utilizing septic tanks.

Table 4-2 indicates that there is no current capacity deficit, either design related or permit related, for the wastewater treatment facilities operating within the County. Connection to centralized sewer is required by the County for platted residential developments if service is available within ½ mile or as required by the individual utilities, expansion of the systems is driven by demand for higher density development patterns or may be required by environmental constraints. Metes and bounds subdivisions and individual homes are required to connect if service is directly available (in front of home). Current County policy allows for residential development with septic tanks at 4 units per acre when a centralized water connection is available and at 2 units per acre when utilizing a septic tank and private well for potable water.

Table 4-1: Existing Structure Count by Wastewater Franchise Area and % Connected

Wastewater Utility	Commercial	Community Facilities	Multi-Family Residential	Single- Family Residential	Commercial Connections	Residential Connections	% Res Connected
City of Milton	887	199	1,061	5,760	462	3,956	69%
Gulf Breeze/ SSRU	1,172	169	2,009	11,348	513	7,335	65%
Holley- Navarre	561	114	1,383	14,205	346	7,275	51%
Navarre Beach	36	23	922	362	10	1,929	100%
Pace	768	89	1,438	16,271	352	5,825	36%
Town of Jay	113	41	30	245	62	253	103%

 

Table 4-2: Wastewater Utility Capacity Analysis and Operational Data

Waste- water Utility	Popu- lation Served	Commer- cial Connec- tions	Residen- tial Connec- tions	Design Capacity gpd	Permit- ted Capacity gpd	Average Daily Flow gpd	Percent Design Capacity	Percent Permitted Capacity	Reuse Flow	Reuse Custo- mers
Pace Water System, Inc.	15,087	352	5,825	5,000,000	1,900,000	1,330,000	27%	70%	1,276,000	448
Navarre Beach	4,996	10	1,929	900,000	900,000	187,000	21%	21%	NA	NA
City of Gulf Breeze/ SSRU	18,998	513	7,335	2,000,000	1,920,000	1,660,000	83%	86%	1,230,000	863
City of Milton	10,246	462	3,956	2,500,000	2,500,000	1,657,000	66%	66%	NA	NA
Holley Navarre Water System, Inc.	18,842	346	7,275	3,240,000	3,240,000	1,820,000	56%	56%	1,566,000	2
Town of Jay	655	62	253	120,000	120,000	59,000	49%	49%	NA	NA

 

4.1.2.2 Level of Service Standard and Concurrency for Wastewater in Santa Rosa County

In 1991, Santa Rosa County established the Concurrency Management System through Ordinance 91-24. The Concurrency Management System is based on the adopted Level of Service (LOS) established in the Infrastructure Element and the Capital Improvements Element. The reservation of capacity is based on the capacity being provided at the LOS standard of a minimum of 90 gallons per capita per day (gpcd).

It is important to understand that level of service criteria central sewer really indicate the ability of the treatment facilities to accommodate demand. This demand is primarily population driven. The LOS standard means, for instance, that a wastewater treatment facility such as the Navarre Beach WWTF would need to be able to treat 90 gallons of influent per person served per day. If a new development were to come on line that needed capacity, planning staff would look at the ability of the WWTF to serve existing customers at that LOS plus the new customers added by the new development. Linear infrastructure such as the necessary lines that make up the water and sewer systems transmission infrastructure face additional challenges. This is where coordination of land use and development approvals becomes very important. Two types of development patterns can be problematic to future development desiring sewer infrastructure, retrofit for environmental reasons or fire protection, and extension of services in general.

These types of development patterns can make future extension cost prohibitive and can "lock in" future development by making extensions difficult.

1)

Leap frog development—development that leaps over large vacant areas; and

2)

Barrier development—development that occurs within relatively close proximity.

In Santa Rosa County, connection to a public sewer system if available (basically in front of home) is required for all single family residential projects requiring a building permit. The County has additional requirements for developers platting new subdivisions that may require the extension of lines to the new development and within the new development. The following table ( Table 4-3 ) summarizes current Land Development Code and Comprehensive Plan policies for central water and sewer.

Table 4-3: Current Central Sewer Policy for Residential Developments Requiring Extension

	LOS (Utility) Requirement	Developer Requirement
Central Sewer	90 gallons per capita per day	For Platted subdivisions only (excluding metes and bounds subdivisions requiring extension)—required to connect if sewer is located within ½ mile of the proposed project. Metes and bounds subdivisions are only required to connect if service is available in front of house. Certain engineering standards also apply and the utility is required to refund the developer one half of the cost to install.

 

Map 4-2 Sewer Franchise Areas of Santa Rosa County