Part dealing damage even when the player stops moving in it

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#1

Hello, I am currently working on a game in which I need the Roblox provided water to deal damage to the player on touch. I have done this by just adding the water and then making an invisible block that doesn’t collide with the player and placed it at the exact position the water is.
This is the script I am using:

script.Parent.Touched:Connect(function(hit)
	if hit.Parent:FindFirstChild("Humanoid") then
		hit.Parent.Humanoid.Health = hit.Parent.Humanoid.Health - 0.5
	end
end)

It’s very basic, I know, but so far it hasn’t lead to any isses. The problem is that today I figured out that it was possible to just not move in the water and it will stop dealing damage. This is the thing I am trying to prevent.
Any help is appreciated!

#2 
local DAMAGE = 10
local INTERVAL = 1/30

local touchingHumanoids = {}
script.Parent.Touched:Connect(function(hit)
	local humanoid = hit.Parent:FindFirstChild("Humanoid")
	if not humanoid or humanoid.RootPart == hit then return end
	
	if touchingHumanoids[humanoid] then
		touchingHumanoids[humanoid] += 1
	else
		touchingHumanoids[humanoid] = 1
	end
end)

script.Parent.TouchEnded:Connect(function(hit)
	local humanoid = hit.Parent:FindFirstChild("Humanoid")
	if not humanoid or humanoid.RootPart == hit then return end
	
	if touchingHumanoids[humanoid] then
		touchingHumanoids[humanoid] -= 1
		if touchingHumanoids[humanoid] == 0 then
			touchingHumanoids[humanoid] = nil
		end
	end
end)

while true do
	for humanoid in pairs(touchingHumanoids) do
		-- if the humanoid is destroyed, remove it from the loop
		if not humanoid:IsDescendantOf(game) then
			touchingHumanoids[humanoid] = nil
			continue
		end
		
		humanoid:TakeDamage(DAMAGE)
	end
	
	task.wait(INTERVAL)
end

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