SwimSmart’s mission is to bring together water safety stakeholders from around the country to standardize water safety tools and best practices, providing beachgoers with consistent water safety messaging regardless of location. Collaboration is the cornerstone of standization, however, various concessions must be made to provide for a simple, streamlined, educational tool. The standards set herein are based upon a decade of work, in consultation with our partners, distilling down the most prevalent and applicable warning systems seen around the country. We recognize that the selection of colors, their assigned meaning, and the inclusion or absence of colors is a strongly debated topic. The combination of defined beach hazards, absence of other hazards, and specific language specifying said hazards is also debated. However, a standardized format had to be settled on. The rational is explained below.
Underlying beach hazards vary by location, however, uniform color coding and warning logic is imperative to streamline public adoption and understanding. While there are a myriad of swim-related hazards that vary from beach to beach it's imperative that the warning system be distilled down to the most prevalent hazards to the public as a whole. The SwimSmart warnings focus on Dangerous Waves and Currents (DW&C), and Water Quality (WQ) Hazards. The warnings target relative hazard to what is referred to as the Average Swimming Capability (ASC) which is averages the swimming capabilities of all swimmers. Again, this is a relative hazard classification warning system, it does not attempt to quantify the level of safety of any specific swimmer. Note, we do not consider hazards such as, but not limited to, hypothermia, shock drowning, drop offs, lightning, diving, sharks, offshore winds, meteotsunamis, tsunamis, seiches, debris, oil spills, water spouts. However, at the discretion of the beach manager the system can be used so. Pier lights refer to walking along and not swimming near a pier or other structure. SwimSmart recommends a 100 foot swimming keepout around a pier. Note, our warnings target relative hazard with respect to ASC and it is understood there are individuals who have no swimming ability. A warning focused on either extreme is ineffectual.
Dangerous waves and currents (DW&C) adopts the standardized color code of the most common implementation of the beach warning flag system - red, yellow, green, purple, double-red. Red - (Required) - High Hazard* Yellow - (Required) - Moderate Hazard* Green - (Required) - Low Hazard* Purple - (Optional) - Stinging Marine Life Double-Red - (Optional) - Water Closed * Hazard refers to Dangerous Waves and Currents
Many inland beaches that do not experience high wave action will experience water quality (WQ) issues. Water quality warnings follow the same general color code - red, yellow, green. Water quality warnings shall be clearly labelled so as to not confuse with DW&C. Red - (Required) - Water Closed** Yellow - (Required) - Advisory* Green - (Required) - No Advisory* * Advisory refers to Water Quality ** Unlike Type 1, water quality warnings designate one red as a closure
Beaches that experience both Type 1 and Type 2 hazards must be consolidated into a single warning system for the sake of the public. Red - (Required) - High Hazard* Yellow - (Required) - Moderate Hazard* Green - (Required) - Low Hazard* Purple - (Optional) - Stinging Marine Life Double-Red - (Optional) - Water Closed** * Hazard refers to Dangerous Waves and Currents AND/OR Water Quality ** For Type 3, Water Quality must use double-red for closure.
For Dangerous Waves and Currents (Type 1) and DW&C + WQ (Type 3) the color code shall adopted the following: red, yellow, green, purple, double-red in that order. Red, yellow, and green are referred to as the primary colors and are required on all SwimSmart BNLs. However, purple and double-red are optional and not always applicable.
The top red light indicates a high hazard situation. The high hazard is a simple way for swimmers to understand that the risk of swimming is at its greatest within this paradigm.
Red is universally understood for “stop”, “danger”, “evacuate”, “denied”, “emergency”, “closed”, etc. For example, traffic lights, toll booths, fire escapes, turnstiles, access controls, emergency vehicle lighting, etc. Red is a suitable color to resemble a high hazard situation.
However, one red light indicates that the level of hazard is high and not that the water is closed. Water closures are linked to local policy decisions that are not universally applicable. Thus, double-red is reserved for closures.
Note: Autonomy will set the BNL red for high risk forecasts.
The yellow light indicates a moderate hazard situation. The moderate hazard is seen as a suitable midpoint where conditions are not deemed low nor high.
Yellow is universally understood for “slow”, “caution”, “prepare”, “advisory”, “wait”, “yield”, etc. For example, traffic lights, cross walks, access controls, construction vehicle lighting, etc. Yellow is a suitable color to resemble a moderate hazard situation.
There is a lot of grey area in determining an appropriate level of hazard and yellow provides flexibility to both the issuer and the public. Yellow also allows for a more graceful transition from green to red when conditions change over time. Without it red would be unreasonably conservative. Yellow allows for greater accuracy when conditions fit between a definite high or low hazard, building more confidence in the public.
Note: Inclusion of yellow in the BNL does not mean the beach is forced to use it. The yellow light is included for completion and standardization; however, it is up to the beach managers to set the colors.
Note: Autonomy will set the BNL yellow for moderate risk forecasts.
The green light indicates a low hazard situation. Green represents low hazard not no hazard as there is always risks to swimming.
Green is a universally understood for “go”, “clear”, “safe”, “pass”, “open”, etc. For example, traffic lights, toll booths, turnstiles, access controls, construction vehicles, etc. As explained in another section, green is seen as the optimal color to indicate a low hazard situation.
However, even in traffic, green lights have further rules of the road (e.g. pedestrian traffic, emergency vehicle priority, etc). This is the case with swim warnings. There are inherit risks to swimming just as there is with driving, however, the warning lights are present to communicate a relative hazard level not indicate whether something is deemed safe to any particular person.
Note: Inclusion of green in the BNL does not mean the beach is forced to use it. The green light is included for completion and standardization; however, it is up to the beach managers to set the colors.
Note: Autonomy will set the BNL green in low risk forecasts.
The purple light indicates stinging marine life. This is a unique hazard that can occur in any water conditions. Stinging marine life (jellyfish) can wash up on shore and remain for multiple days thereafter. This poses a unique hazard that is not capturable by the primary tiered hazard classification.
Purple is not universally associated with typical warning systems. Purple uniquely and dramatically differentiates itself from all other primary colors. Purple combined with red can be common and will not give them same false impression as red and blue together.
Purple is used instead of blue due to mixing red and blue may cause confusion to the public. Therefore, blue is reserved for active emergencies.
Note: Including purple is optional and is not applicable for all beaches.
Note: Autonomy does not support purple, it can only manually be set.
The second bottom red (e.g. double-red) light is always paired with the top red light. When both the top and bottom red light, two reds at once (e.g. double-red) are on it indicates that swimming is prohibited. Again, it’s not possible for only the bottom red to illuminate. Double-red allows for beaches who wish to adopt enforcement measures to clearly indicate that the swimming is not allowed.
However, not all beaches wish to close their beach. Whether or not this is prudent, beach closures are a local policy decision and not a measure of hazard.
Double-red isolates autonomously issued high swim risk forecasts from local policy decisions. It also provides a very explicit distinction from beaches that may not issue closures but still operate the standardized hazard warning system.
Note: Including double-red is optional and is not applicable for all beaches.
Note: Autonomy does not support double-red, it can only be manually set.
Red, Yellow, Green (RYG-1 / RYG-3) Type 1 and 3 - Base signs that include the three primary colors. All BNLs will, at a minimum, include these three colors. Note that each warning light follows the same order from top to bottom: red, yellow, green, purple, double-red. This order shall be consistent for all BNLs. The relevant information next to each colored orb, or traffic light BNL, is color coded the same. Each sign includes, at a minimum, information in English and Spanish. Additional languages can be requested and will be single line of the same font as and below the Spanish text. Please contact SwimSmart if additional languages are required. The only difference between Type 1 and 3 RYG signs is the inclusion of "and/or" contamination in medium and high hazard. The low hazard information is the same between Type 1 and 3 signs. Red, Yellow, Green, Double-Red (RYGC-1 / RYGC-3) Type 1 and 3 - These signs include the addition of double-red for water closed situations. Again, double-red is optional and is differentiated from a single, top, red which designates high hazard. Double red is a local beach policy decision. Enforcement of such a closure is up to the local beach managing authorities alone unless specified otherwise by local, state, or federal law. Red, Yellow, Green, Purple, Double-Red (RYGPC-1 / RYGPC-3) Type 1 and 3 - These signs include the addition of purple for stinging marine life. As mentioned, purple is optional.
Many inland beaches experience fluctuations in various water contaminants. Thorough testing and public notification processes are in place to warn the public of dangerous swimming conditions. Type 2 warnings, for water quality exclusively, contain a three tier hazard red, yellow, green designating water closed, advisory, and no advisory respectively. Unlike Type 1 warnings the single top red replaces the double red to differentiate it from DW&C. However, for Type 3 warnings WQ must conform to the double-red paradigm for water closed. The differentiation between the two (Type 2 and 1/3) is important to explicitly distinguish the underlying hazards - WQ and DW&C. While Type 3 signage won't specify the underlying cause, WQ v.s. DW&C, the same logical warning structure is used to streamline consolidation.
While piers typically refer to raised structures on piles that extends perpendicular out into the water; in the Great Lakes many "piers" are low concrete pathways that sit only a few feet above the normal water line. High waves and winds can cause wash off pushing individuals into the water. This specialty standalone red light is focused on specifically closing the pier. This light does not indicate hazards swimming near a pier. SwimSmart recommends a 100 foot swimming keep out around all piers, rock walls, or other permanent structures.
If a beach wishes to include additional information beyond that of the standarized warning sign, they can include an appendage sign. These are smaller separate signs that attach around the primary sign. The appendage sign shall not include any information that contradicts the primary sign.
The National Weather Service swim maps switched over to a new color code and map around 2020. The changes were made in consultation with the United States Lifesaving Association (USLA). The argument is made that green is sending a false sense of security and that swimming is never safe. Every swimmer has different abilities and a green/grey to one swimmer may be different to another.
While in most cases green and grey indicate a Low Hazard or Risk situation. We understand some organizations such as USLA prefer grey, we decided against grey for the following reasons,
Logical Arguments:
Green as a indication color is universally understood while grey is not. Regardless of it’s implicit meaning out of context, education must compliment any safety policy, whether green or grey, and this is no different. The focus should be on uniformity and education less the color.
Green flag systems are already implemented and well established around the country. Changing color code more broadly is a considerable undertaking and until obvious benefits are shown it’s unlikely to change. Beaches that prefer grey over green never use either to begin with.
We’re limited on the number of colors in which are clearly differentiable from one another. Especially in high glare situations. Grey is not feasible so white is the only option. However, white is reserved for generic lighting which is used to illuminate our signs, callboxes, or area lighting for dawn/dusk emergency use.
Technical Realities:
A reality of a lighted warning system is that grey will really have to be white. White light will appear as any other illumination such as headlights, streetlights, etc. In high glare situations it becomes very difficult for white light to overcome glaring cloud conditions. White light will quickly fade into the background after a few hundred feet. This is already somewhat true for our yellow lights. There is no sense in exasperating this issue.
White light is technically a combination of various colors, in the context of LEDs a lot of white lights produce the color through combined colors which typically makes them more inefficient for the same given output power.
Based upon the light efficiency function (LEF) of the human eye, green is the most efficient while blue and purple are the least. Many white LEDs use a combination of blue to produce white. However, at night time blue is actually the most efficient, this is why many white LEDs for illumination purposes utilize a manipulated blue light spectrum.
Marine life such as sea turtles are sensitive to light wavelengths less than 560nm. While green is applicable here, blue has substantially smaller wavelengths. Thus, many localities have restrictions on lighting; white utilizing blue manipulation requires excess output power compared to green for the same visibility to the LEF. Note that our lights operate dawn to dusk and turn off at night.
Ironically enough, purple (for stinging marine life) is the lowest wavelength and will require substantial corrective measures to be useful in these environments. Again, further exasperating problems where there don’t need to be is unnecessary. 
Economic Arguments:
Adding additional colors adds system complexity and additional part numbers. These extra part numbers translates into lower averaged quantities, additional engineering and support costs, per light which results in higher costs to the beaches. White lighted units will be rare and exceptionally more expensive for an inferior performing light.
The warning system operates as a finite state machine that visually displays the relative ASC hazard level. The warning tiers are relative to one another with respect to ASC. Therefore, the warnings should always have at least one of the primary colors on to indicate relative hazard.
While its certainly true that the number of hazard tiers (high/moderate/low) could be reduced (or even increased), it would not make sense dropping out the bottom. The only tenable position if green is removed is that the system must always be either yellow or red. Having a “green less” low hazard indication where the lights are off would confuse the public on whether the warning is not applicable to those listed or whether the system is operational at all.
It is true that the lights do have Sleep (Power Saving) Modes that turn the light off at night. However, this is reserved for park closed hours. Having lights off during a bulk of the swimming day renders a warning system pointless and ineffectual. A better solution would be white/grey over nothing.
It should be reiterated that just because green is included in our signage for completeness and uniformity, does not require the beach manager to use green. Therefore, a concession with aims of standardization is to include green in the signs but not require its usage. There are beaches around the country that have green on their signs but never use them. This system would be no different.
There are a few realities of Light Emitting Diodes (LED), visible light and the human eye, and discernibility in a high glare situation. The goal should be to distil the warning down into the minimal useful “buckets” while not including colors that can be misconstrue from one another. Other possible colors that either are included in our units or excluded for reasons given:
White (Reserved) – is reserved for area, flood, or faceplate lighting. White LEDs are ideal for illumination at night, however, not effective during the day. We use white LEDs to light up our signage and phones for nighttime emergencies.
Blue (Reserved) – is reserved for emergencies only. Including blue within the BNL may confuse swimmers if ever a red and blue combination is possible. Due to it’s universal understanding that blue relates to “emergency”, “police”, “safety” and our relationship with Code Blue Corporation we’ve reserved blue for active emergencies. Blue lights therefore are only active when emergency equipment is activated to clearly indicate it’s intrinsic intent. Also given it’s low wavelength its not recommended to have a light of this nature always on to protect marine life.
Orange (Excluded) – is typically difficult to differentiate from yellow or red in high glare situations. Our ‘yellow’ lights are actually a hue of amber and could be argued to be orange.
Cyan (Excluded) – is also excluded as to not confuse with blue and follows the same arguments as blue as to not include in the BNL.
For the sake of the public, standardized messaging is important. However, just because a color is required on a sign does not require the beach managers to use said color. An example is a very dangerous area in which swimming is always discouraged. The beach manager can set the light to red and keep it red forever.
It should be noted that not all of the colors are required, only the primary (red, yellow, green). Purple and double-red for Type 1 and 3 systems are optional and not applicable for all beaches. The standardization focuses on common colors indicating the same thing.
While the primary sign that includes the traffic light is standardized and cannot be changed, the one exception is including additional languages. The dimensions of the sign is fixed so realistically only two “alternate” languages can be included on a given sign. If there are language barriers unique to your community please contact us. SwimSmart signs come standard in English and Spanish.
Alternatively, appendage signs are permissible for any additional information or languages unique to your beach. These additional signs are attached either above or below the primary sign and include other information such as logos, QR codes, websites, phone numbers, or park rules. The only restriction on appendage sign is that it cannot contradict the primary sign.
In an effort to combine existing beach flag with water quality placards warning systems certain concessions must be made.
It’s important that Water Quality only systems differentiate themselves from anything relating to Dangerous Waves and Currents whether Type 1 or 3. There are lots of inland beaches of which do not experience Dangerous Waves and Currents and, thus, it does not make sense to require an additional red light. However, the same essence should be as consistent as possible.
When combining DW&C and WQ for Type 3, Water Quality closures now use the standard double-red; same as DW&C. Double-red’s can be considered as one of the differentiators to indicate the system relates to DW&C.