diff --git a/core/src/utils.jl b/core/src/utils.jl
index 155de2b70..65cb8372c 100644
--- a/core/src/utils.jl
+++ b/core/src/utils.jl
@@ -906,13 +906,13 @@ end
 Function that goes smoothly from 0 to 1 in the interval [0,threshold],
 and is constant outside this interval.
 """
-function reduction_factor(x::Real, threshold::Real)::Real
+function reduction_factor(x::T, threshold::Real)::T where {T <: Real}
     return if x < 0
-        0.0
+        zero(T)
     elseif x < threshold
         x_scaled = x / threshold
         (-2 * x_scaled + 3) * x_scaled^2
     else
-        1.0
+        one(T)
     end
 end
diff --git a/core/test/utils.jl b/core/test/utils.jl
index a0ae96bd7..0544cbe99 100644
--- a/core/test/utils.jl
+++ b/core/test/utils.jl
@@ -206,3 +206,13 @@ end
     @test isempty(fv)
     @test length(fv) == 0
 end
+
+@testset "reduction_factor" begin
+    @test Ribasim.reduction_factor(-2.0, 2.0) === 0.0
+    @test Ribasim.reduction_factor(0.0f0, 2.0) === 0.0f0
+    @test Ribasim.reduction_factor(0.0, 2.0) === 0.0
+    @test Ribasim.reduction_factor(1.0f0, 2.0) === 0.5f0
+    @test Ribasim.reduction_factor(1.0, 2.0) === 0.5
+    @test Ribasim.reduction_factor(3.0f0, 2.0) === 1.0f0
+    @test Ribasim.reduction_factor(3.0, 2.0) === 1.0
+end