In the United States, drowning is the second leading cause of death due to unintentional injury for children 14 years old and younger.[
] In addition, there are many children who survive a drowning incident, with eight times as many children experiencing a nonfatal drowning than a fatal drowning.[ 1 ] Even when a child survives, drowning often requires medical attention. More than 40% of drownings that are treated in an emergency department need further care compared with 8% for other types of unintentional injuries.[ 1 ] For some, drowning injuries can result in long-term neurological damage and disability.[ 1 ] 1
The risk of a drowning incident resulting in long-term neurological deficits or death increases with increased submersion time.[
2 ] When seconds matter, it is imperative that caregivers, lifeguards, and other pool, child care, or camp staff responsible for children around water are able to respond to a drowning incident as quickly as possible. 3
During camp and child care outings to the pool, lifeguards and camp or child care staff may be the only adults supervising groups of children. Although lifeguards are highly trained to identify swimmers who are drowning or at-risk, there may be only one or two lifeguards monitoring large groups of children in a crowded pool. In addition, camp counselors and child care providers may offer supplemental supervision, may have little or no training in how to monitor swimmers, identify drowning, or respond to a drowning incident. Research shows that nonlifeguards are not as fast or accurate as lifeguards at identifying distressed swimmers.[
] Solutions are needed to help lifeguards and staff identify children who are drowning or engaged in activities that increase drowning risk and to decrease submersion time when a drowning incident occurs. There is a need to improve safety for group pool outings that are common in camp and child care settings so that drowning incidents can be responded to as quickly as possible. 4
Despite there being many water safety devices and barriers available on the market, there is almost no research available on the effectiveness of any of these devices or barriers to prevent drowning except pool fencing and life jackets.[
] Many water safety technology options are designed to prevent access to home pools when it is not swim time (e.g., pool alarms, pool covers, door and window locks, door and window alarms, fencing, fence gates, and gate locks). Life jackets and other flotation devices are designed to be fitted and used by a single child while in or near water but may be cumbersome to store or transport for large groups of swimmers needing varying sizes. In addition to devices intended to prevent drowning, there are a number of drowning detection devices that can be used to monitor whole pools or groups of swimmers.[ 5 ] However, many use video-based monitoring that would not be useful in open water, monitor swimmer behavior with complex algorithms that would be challenging to test effectiveness in a real drowning scenario, or need to be installed in a pool and so are not portable or useful in open water.[ 6 7 ] For this research, we chose to study the WAVE 8 ™ Drowning Detection System because the simplicity and reliability of the submersion detection, possible deployment in pools or open water, and system portability made it a good fit for use with camp or child care groups while they are in or around water.
The aim of this study was to do a preliminary evaluation of a commercial drowning detection system that can be used in a group swim setting to supplement lifeguard and camp staff supervision. We will report the number of alerts during the data collection period and common causes for system alerts, as identified by the lifeguards and camp counselors using the system. We will also assess staff attitudes about the system.
™ Drowning Detection System
™ Drowning Detection System (WAVE) is a portable early warning detection system employed for drowning prevention developed by WAVE Systems Inc. (Norwalk, CT, USA). The system consists of a set of headbands worn by swimmers [ Figure 1], a few bracelets worn by staff, and a hub with an audible alarm. When a headband Bluetooth signal is not detected by the system hub after a preset number of seconds, the bracelets will vibrate and/or the alarm will sound. Bluetooth signals are not detected by the system when the headband is submerged in the pool because the head of a swimmer is submerged. The alerts will stop on their own if the headband re-surfaces or can be suppressed manually using a tablet interface. In addition, Bluetooth signals may not be detected, resulting in alerts, if the headband falls off while submerged, is taken off and submerged by hand, or is worn outside of the pool area. These types of alerts may be stopped when the submerged headband floats to the surface, is put back on, or is retrieved from the person who left the pool area. The aim of the system is to supplement standard lifeguard pool monitoring by detecting submerged swimmers earlier than they may be detected with visual scans of the pool area. Figure 1:
(a) WAVE swimmer headband, staff bracelets, and hub; (b) WAVE headbands in use
The WAVE w100 system was deployed at one indoor Young Men's Christian Association (YMCA) pool in Central Texas during swim time for an on-site summer camp. During the times the WAVE system was deployed, the pool was used exclusively for children 8–13 years old attending the YMCA camp. All campers were required to wear the WAVE headbands while in the pool, with high compliance maintained by camp staff. Groups of 40–60 campers were in the pool for 1 h swim sessions for 3 h each day, 5 days a week. A total of 120–180 campers used the device each day. Following 1 week of training, data on alerts were collected for the 120 h it was in use over 8 weeks during June, July, and August 2021.
A prospective observational study was conducted to evaluate WAVE alerts and staff attitudes about its use and usefulness. The study was reviewed by an Institutional Review Board and determined to be an evaluation, not human subject's research. Research adhered to EQUATOR network STROBE guidelines.
Due to the low likelihood of even one drowning incident occurring during the 8-week data collection period, this evaluation assessed the incidence of risky pool behavior as a surrogate measure indicating drowning risk. In addition, we assessed the incidence of alerts triggered by false alarms. Our primary outcome measure was the number of alerts received by the WAVE system during the time period, which shows how frequently a headband was removed from the pool area or submerged longer than 20 s. In addition, we asked staff to identify the most common causes of alerts to evaluate the relative frequency of risky behavior and false alarms. Our secondary outcome was reported attitudes of the camp staff about using the WAVE system. In addition, the camp director provided written answers to questions on camp attendance, device deployment, and whether there were any incidents in the pool during the data collection period requiring rescue or medical treatment.
WAVE alert data
Based on the recommendation from WAVE Systems, Inc., and initial device testing, the WAVE staff bracelets were set to vibrate after a headband had been submerged for 20 s, and the auditory alarm was set to go off after 30 s of submersion. If the signal returned (e.g., from a submerged swimmer surfacing or staff retrieving a headband from someone who left the pool area), then the alert would stop on its own. If the signal did not stop, pool staff could suppress the signal on a tablet, choosing whether the reason for the suppression was Swimmer OK, Backstroke, or Testing Wearables (e.g., if a staff member submerged a headband to demonstrate the system or test a bracelet). Data on when alerts started, stopped, or were suppressed within the system were provided to the research team by WAVE Systems Inc., for research purposes.
Pool staff survey
A total of 30 counselors and six lifeguards used the WAVE system during the summer. All camp counselors, lifeguards, and administrative staff who were on duty in the pool area during WAVE deployment were eligible to participate. On the last day of the camp session, the pool and camp staff who were on-site over the lunch hour were asked to take an an anonymous online survey about the WAVE system using their phones or a provided tablet. Staff were verbally told by the researcher that they were not required to take the survey. Each participant also reviewed and agreed to an online consent document before starting the survey. The online survey asked what role the staff member played at the pool or camp and included open-ended questions about what the staff member liked or disliked about WAVE. The survey also asked what they thought the top three reasons were for the WAVE system to initiate alerts during camp, with a drop-down menu of 11 options. The reasons for alerts options were classifications developed by WAVE, Inc., to track alerts within their software. Participants were also asked to rate their agreement with 11 Likert scale statements about the use or usefulness of the system. The Likert scale statements were developed internally by the researchers based on discussions with the camp director about staff experiences with WAVE during the initial week of testing and reviews of device effectiveness research.[
] The survey was tested on camp and research staff during development. Face validity was assessed through reviews by three experts in the field. 9 RESULTS
During the 8-week data collection period, there were 210 total alerts, with an average of 5.25 alerts for each of the 3-h days the system was in use. Of these alerts, 207 stopped without needing to be suppressed. There were three alerts where the system did not stop on its own, requiring the signal to be suppressed manually. For all suppressed alerts, the reason selected was Swimmer OK.
All 15 staff who were present on the last day of camp and were invited to participate took the survey. Of the staff surveyed, 60% were camp counselors, 33% were lifeguards, and 7% were administrative staff. Most staff were employed for their first season in a position where they have some responsibility for the safety of children in a swimming pool, with 60% employed for less than a year, 7% 1–2 years, 27% 3–5 years, and 7% more than 5 years.
Reasons for alerts
The camp director reported that there were no incidents during the data collection period where a swimmer needed to be rescued or required medical assistance due to drowning. YMCA staff reported the most common reasons for an alert going off were due to a Bathroom or exit walk-away or Underwater play [e.g., handstand;
Table 1]. Other common reasons involved Device held underwater, but did not need help and underwater Breath holding. None of the staff reported that common reasons for WAVE alerts involved a Swimmer signaling for help or Device malfunction. Table 1:
Percentage of staff reporting three most common reasons for WAVE alert
Usefulness of WAVE system
Staff agreement with statements about the usefulness of the WAVE system varied [
Table 2]. The greatest agreement was for the statement. Using the WAVE drowning detection system could help save someone's life, with 93% agreeing or strongly agreeing. There was also 93%–100% agreeing or strongly agreeing with two statements that the system is easy to learn and use. The lowest agreement was with the comfort of the headbands, with 66% disagreeing or strongly disagreeing with Children do not mind wearing the WAVE headbands in the pool. There were not strong attitudes about the number of false alarms, with 60% selecting neutral. Table 2:
Percentage of staff rating agreement with statements about WAVE
In answers to an open-ended question about the benefit of the WAVE system [
Table 3], most comments focused on the protection it added for the swimmers and the extra reassurance it gave the lifeguards and camp counselors. In addition, comments highlighted how it brought attention to how long kids were underwater, offering a useful way to monitor risky behavior. Table 3:
What is the most important benefit of using the WAVE drowning detection system?
In answers to an open-ended question about what the YMCA staff did not like about using the WAVE system [
Table 4], comments focused on the headbands falling off, being uncomfortable for the children to wear, and alerts from when kids wore the headbands into the bathroom. Table 4:
What did you not like about using the WAVE drowning detection system?
The findings of this study show that lifeguards and camp counselors who deployed the WAVE system in a busy pool believe that it could help save someone's life. In addition, they found it easy to learn and use. Alerts most often occurred due to risky play behavior by children and when children left the pool area without taking the headband off. Results highlight a positive attitude about the way the system made staff more aware of how long swimmers are underwater. Comments suggest that the alerts due to risky play behavior were useful, supplementing staff monitoring in a positive way. Attitudes about false alarms were neutral. Comments highlighted that headband comfort and fit could be improved.
The WAVE system was deployed in a pool with 40–60 children in it at all times. Despite such high usage, the WAVE system gave an alert, on average, one or two times per hour. These alerts often highlighted risky behavior by the children, like breath holding or doing handstands. This kind of play is discouraged by lifeguards due to the danger it poses if the child cannot get back to the surface before they need air. Several incidents where people have blacked out and drowned from underwater breath holding has highlighted the need to limit such risky pool behavior.[
Comments by the pool staff suggest that WAVE alerts due to risky pool behavior should not be considered false alarms since the alerts serve the positive purpose of bringing attention to behavior that could lead to a drowning incident, allowing them to limit risky play more effectively. Comments from pool staff highlighted that they liked the way the WAVE system supplemented their visual monitoring of the pool and offered reassurance that they would know if someone was drowning. In addition, they commented on how it added an additional layer of protection, in line with the American Academy of Pediatrics recommendation that there be multiple layers of protection against drowning in place.[
] Due to the potential for the WAVE system to improve lifeguard and pool staff surveillance, the system could improve drowning prevention in addition to the primary aim of drowning detection. This potential is supported by prior research showing that training can improve lifeguard surveillance and that when surveillance improves, risky behavior by pool patrons decreases.[ 5 ] In addition, improved lifeguard monitoring and faster drowning detection offered by the WAVE system could reduce submersion time during a drowning incident, which could improve the chances of survival and neurological outcomes of a submersion event.[ 11 2 ] 3
Participants showed attitudes between neutral and agreement with statements about the system increasing confidence in being able to provide a safe swimming environment, helping to identify and respond to a drowning swimmer more quickly, and accurately identifying swimmers who are submerged too long. A majority of participants had a neutral view about being able to use the WAVE system when working at a pool in the future. None of the participants identified any potential for increasing drowning risk with the use of the WAVE system, likely due to the ease of learning and use of the system.
A child leaving the pool area with the headband on was noted as one of the most common reasons for an alarm. This happened because the Bluetooth signal was lost when there was a wall between the headband and hub, which generally prompted a counselor to have to run after the kid to get the headband back so the alarm would go off. Dislike of the alarms that occurred when a child walked into the bathroom with the headband on was noted by a few participants in their comments. However, overall, the participants did not believe that there were too many false alarms for the system to be useful, with the majority of participants having a neutral attitude about false alarms. Few alarms were due to unknown reasons. WAVE Systems, Inc., have noted that alarms can be triggered by underwater swimming or swimming backstroke or freestyle with the head low in the water, but these reasons for alerts are likely more common with adults swimming laps and during swim team practices, not in the camp environment studied for this project.
Swimmer needed assistance was selected as the third-most common reason for an alert by one participant. There were no major incidents when swimmers needed emergency assistance during the data collection period, so it is likely that this reason was interpreted as meaning that swimmers needed assistance with the headbands when they would fall off or were uncomfortable. Comments about what staff disliked highlighted issues with the headband comfort and likelihood it would fall off. In addition, the majority of participants disagreed with the statement that children do not mind wearing the WAVE headbands in the pool. It is expected that the continued development of the WAVE headbands will address these concerns.
This study was limited by data collection for alerts being collected only during the 8-week window of time a summer camp was in session. In addition, the survey was limited by having few staff eligible to take the survey and fewer still working during the time when the survey data were collected. Another limitation of the study is that data were not collected on how often there was risky pool behavior that the WAVE system did not detect.
A proper evaluation of the effectiveness of a device should address how often that device achieved its aim. This evaluation was limited in what it could measure or conclude based solely on alerts and staff attitudes. Because drowning incidents are rare for any one facility, it would be difficult to assess whether WAVE was effectively preventing drowning or reducing submersion time during a drowning incident. The WAVE
™ Drowning Detection System is very reliable at doing what the technology is supposed to do: detect when the headband Bluetooth signal disappears. Staff reported that the device never malfunctioned and that it consistently went off when the Bluetooth signal disappeared, either blocked by water or by a concrete wall. It is likely that failures to identify submerged swimmers when WAVE was in use would be due to deployment issues, like children removing their headbands prior to an incident, rather than a failure of the technology itself. Ongoing improvements to headband fit and deployment protocols will likely further boost the potential effectiveness of WAVE.
This study demonstrated the benefits of using the WAVE system with groups of children monitored by camp staff in a swimming pool. The WAVE system would likely have usefulness in other group swimming scenarios, such as child care pool trips, children's swim teams and swim lessons, and in swimming pools with regular patrons. In addition, the system could be used with adults during lap swimming and aquatic exercise, for masters swim teams, and in private pools without lifeguards, like retirement facilities. Future research is needed to assess the many devices and barriers that can improve water safety or detect drowning to evaluate whether they are effective at reducing drowning risk or submersion time.
Overall, this study offered support for the usefulness of the WAVE™ Drowning Detection System when deployed in pools with large groups of children. Although there were no drowning incidents in the pool while it was deployed, staff reported that they believed it could help prevent drowning and keep children safer.
Research quality and ethics statement
This study was reviewed by the Health Sciences Institutional Review Board at the University of Texas at Austin (Approval No. STUDY00001416; Approval date July 14, 2021) and determined to be not human subjects research. The authors followed the applicable EQUATOR Network guideline, specifically the STROBE guideline, during the conduct of this research project.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
We would like to thank Bret Kiester, YMCA of Austin Executive Director of Aquatics and Camp Moody, for his assistance coordinating the survey evaluation and providing supplemental information about the WAVE deployment. We thank Mark Caron, CEO of WAVE Systems Inc., for providing the alert data used for this research.
1. Centers for Disease Control and Prevention, National Center for Injury Prevention and Control. Drowning Facts. Available from:
. [Last accessed on 2022 Feb 07]
2. Quan L, Wentz KR, Gore EJ, Copass MK. Outcome and predictors of outcome in pediatric submersion victims receiving prehospital care in King County, Washington Pediatrics. 1990;86:586–93
3. Koon W, Clemens T, Bierens J, Quan L. Studying outcome predictors of drowning at the scene: Why do we have so few answers Am J Emerg Med. 2021;46:361–6
4. Laxton V, Guest D, Howard CJ, Crundall D. Search for a distressed swimmer in a dynamic, real-world environment J Exp Psychol Appl. 2021;27:352–68
5. Denny SA, Quan L, Gilchrist J, McCallin T, Shenoi R, Yusuf S, et al Prevention of drowning Pediatrics. 2021;148:1–23
6. Dhande B, Kothawade Y, Kulkarni A, Askhedkar A. Comprehensive survey of drowning detection and rescue techniques Int Res J Eng Technol. 2018;5:2028
7. Salehi N, Keyvanara M, Monadjemmi SA. An automatic video-based drowning detection system for swimming pools using active contours IJ Image Graph Signal Process. 2016:1–8
8. Dehbashi F, Ahmed N, Mehra M, Wang J, Abari O. SwimTrack: Drowning Detection using RFID Proceedings of the ACM SIGCOMM 2019 Conference Posters and Demos. 2019:161–2
9. Subermaniam K, Welfred R, Subramanian P, Chinna K, Ibrahim F, Mohktar MS, et al The effectiveness of a wireless modular bed absence sensor device for fall prevention among older inpatients Front Public Health. 2016;4:292
10. Shallow Water Blackout Prevention. Available from:
. [Last accessed on 2022 Feb 07]
11. Schwebel DC, Lindsay S, Simpson J. Brief report: A brief intervention to improve lifeguard surveillance at a public swimming pool J Pediatr Psychol. 2007;32:862–8