diff --git a/ChangeLog b/ChangeLog
index 1abe3e0b4648c68c70bd46f9fc907de407bc4c85..a8381c949312a3ec4f8c6dc67f1045f28e2c247b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2018-05-15 Richard Larsson <ric.larsson@gmail.com>
+
+	* ARTS-XML-DATA-2-3-26
+	
+	* spectroscopy/nlte:  Added as storage for rate constants.
+	Presently only contains numbers for H2O-H2O collisions.  Data
+	prepared by Takayoshi Yamada, README source its origin
+
 2018-05-04  Oliver Lemke  <olemke@core-dump.info>
 
 	* ARTS-XML-DATA-2-3-25
diff --git a/spectroscopy/nlte/H2O/README b/spectroscopy/nlte/H2O/README
new file mode 100644
index 0000000000000000000000000000000000000000..cdcc1b108d0e2cbab5cadc348f0b786558523199
--- /dev/null
+++ b/spectroscopy/nlte/H2O/README
@@ -0,0 +1,5 @@
+Collisional parameters used by rotational water non-lte calculations.
+
+Unit of the data is in per second per cubic meter.
+
+Data is from H2O-H2O Collision Rate Coefficients by G. Buffa et al. The Astrophysical Journal Supplement Series, 128: 597-601, 2000 June
\ No newline at end of file
diff --git a/spectroscopy/nlte/H2O/nlte_collision_coefficients.xml b/spectroscopy/nlte/H2O/nlte_collision_coefficients.xml
new file mode 100644
index 0000000000000000000000000000000000000000..33657f18e934d5d9de8e945f2b3f5c5bf7294c29
--- /dev/null
+++ b/spectroscopy/nlte/H2O/nlte_collision_coefficients.xml
@@ -0,0 +1,203 @@
+<?xml version="1.0"?>
+<arts version="1" format="ascii">
+<Array nelem="9" type="GriddedField1">
+<GriddedField1>
+<Vector name="Temperature" nelem="8">
+1.0000000e+02
+2.0000000e+02
+3.0000000e+02
+4.0000000e+02
+5.0000000e+02
+6.0000000e+02
+7.0000000e+02
+8.0000000e+02
+</Vector>
+<Vector name="Collision rate" nelem="8">
+1.4130000e-15
+9.0662000e-16
+8.0830000e-16
+7.3238000e-16
+6.7407000e-16
+6.3072000e-16
+5.9562000e-16
+5.6843000e-16
+</Vector>
+</GriddedField1>
+<GriddedField1>
+<Vector name="Temperature" nelem="8">
+1.0000000e+02
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+8.0000000e+02
+</Vector>
+<Vector name="Collision rate" nelem="8">
+1.5690000e-15
+1.1088000e-15
+9.5641000e-16
+8.7828000e-16
+8.2423000e-16
+7.8219000e-16
+7.4773000e-16
+7.1600000e-16
+</Vector>
+</GriddedField1>
+<GriddedField1>
+<Vector name="Temperature" nelem="8">
+1.0000000e+02
+2.0000000e+02
+3.0000000e+02
+4.0000000e+02
+5.0000000e+02
+6.0000000e+02
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+8.0000000e+02
+</Vector>
+<Vector name="Collision rate" nelem="8">
+1.0440000e-15
+1.0316000e-15
+1.0493000e-15
+1.0512000e-15
+1.0414000e-15
+1.0271000e-15
+1.0097000e-15
+9.9065000e-16
+</Vector>
+</GriddedField1>
+<GriddedField1>
+<Vector name="Temperature" nelem="8">
+1.0000000e+02
+2.0000000e+02
+3.0000000e+02
+4.0000000e+02
+5.0000000e+02
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+8.0000000e+02
+</Vector>
+<Vector name="Collision rate" nelem="8">
+1.1240000e-15
+8.1028000e-16
+6.9618000e-16
+6.3286000e-16
+5.8657000e-16
+5.4907000e-16
+5.1766000e-16
+4.9191000e-16
+</Vector>
+</GriddedField1>
+<GriddedField1>
+<Vector name="Temperature" nelem="8">
+1.0000000e+02
+2.0000000e+02
+3.0000000e+02
+4.0000000e+02
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+</Vector>
+<Vector name="Collision rate" nelem="8">
+1.2690000e-15
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+6.5058000e-16
+6.2445000e-16
+</Vector>
+</GriddedField1>
+<GriddedField1>
+<Vector name="Temperature" nelem="8">
+1.0000000e+02
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+3.0000000e+02
+4.0000000e+02
+5.0000000e+02
+6.0000000e+02
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+8.0000000e+02
+</Vector>
+<Vector name="Collision rate" nelem="8">
+3.3040000e-16
+2.9924000e-16
+2.5270000e-16
+2.1933000e-16
+2.0000000e-16
+2.0000000e-16
+2.0000000e-16
+2.0000000e-16
+</Vector>
+</GriddedField1>
+<GriddedField1>
+<Vector name="Temperature" nelem="8">
+1.0000000e+02
+2.0000000e+02
+3.0000000e+02
+4.0000000e+02
+5.0000000e+02
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+8.0000000e+02
+</Vector>
+<Vector name="Collision rate" nelem="8">
+1.0650000e-15
+9.7835000e-16
+8.5349000e-16
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+6.9244000e-16
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+6.0074000e-16
+5.6979000e-16
+</Vector>
+</GriddedField1>
+<GriddedField1>
+<Vector name="Temperature" nelem="8">
+1.0000000e+02
+2.0000000e+02
+3.0000000e+02
+4.0000000e+02
+5.0000000e+02
+6.0000000e+02
+7.0000000e+02
+8.0000000e+02
+</Vector>
+<Vector name="Collision rate" nelem="8">
+3.1740000e-16
+4.1129000e-16
+4.9368000e-16
+5.4977000e-16
+5.8441000e-16
+6.0469000e-16
+6.1607000e-16
+6.2035000e-16
+</Vector>
+</GriddedField1>
+<GriddedField1>
+<Vector name="Temperature" nelem="8">
+1.0000000e+02
+2.0000000e+02
+3.0000000e+02
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+</Vector>
+<Vector name="Collision rate" nelem="8">
+1.1220000e-15
+1.1027000e-15
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+8.7828000e-16
+8.0046000e-16
+7.4078000e-16
+6.9276000e-16
+6.5451000e-16
+</Vector>
+</GriddedField1>
+</Array>
+</arts>
diff --git a/spectroscopy/nlte/H2O/nlte_collision_identities.xml b/spectroscopy/nlte/H2O/nlte_collision_identities.xml
new file mode 100644
index 0000000000000000000000000000000000000000..a939b2c1ff9dd0d756d11de9499f71428ab02f69
--- /dev/null
+++ b/spectroscopy/nlte/H2O/nlte_collision_identities.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0"?>
+<arts version="1" format="ascii">
+<Array nelem="9" type="QuantumIdentifier">
+<QuantumIdentifier>H2O-161 TR UP J 1 Ka 1 Kc 0 LO J 1 Ka 0 Kc 1</QuantumIdentifier>
+<QuantumIdentifier>H2O-161 TR UP J 2 Ka 1 Kc 2 LO J 1 Ka 0 Kc 0</QuantumIdentifier>
+<QuantumIdentifier>H2O-161 TR UP J 2 Ka 2 Kc 1 LO J 1 Ka 1 Kc 0</QuantumIdentifier>
+<QuantumIdentifier>H2O-161 TR UP J 2 Ka 2 Kc 1 LO J 2 Ka 1 Kc 2</QuantumIdentifier>
+<QuantumIdentifier>H2O-161 TR UP J 3 Ka 0 Kc 3 LO J 2 Ka 1 Kc 2</QuantumIdentifier>
+<QuantumIdentifier>H2O-161 TR UP J 3 Ka 1 Kc 2 LO J 2 Ka 2 Kc 1</QuantumIdentifier>
+<QuantumIdentifier>H2O-161 TR UP J 3 Ka 1 Kc 2 LO J 3 Ka 0 Kc 3</QuantumIdentifier>
+<QuantumIdentifier>H2O-161 TR UP J 3 Ka 2 Kc 1 LO J 2 Ka 1 Kc 2</QuantumIdentifier>
+<QuantumIdentifier>H2O-161 TR UP J 3 Ka 2 Kc 1 LO J 3 Ka 1 Kc 2</QuantumIdentifier>
+</Array>
+</arts>