# Deleting waters from hydrophobic core

**URL:** <https://gromacs.bioexcel.eu/t/deleting-waters-from-hydrophobic-core/9746>\
**Category:** User discussions\
**Created:** [July 25, 2024, 10:02pm UTC](https://gromacs.bioexcel.eu/t/deleting-waters-from-hydrophobic-core/9746 "2024-07-25T22:02:26Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![lipidsolidarity](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/lipidsolidarity/32/3577_2.png) [@lipidsolidarity](https://gromacs.bioexcel.eu/u/lipidsolidarity)\
**Post date:** [July 25, 2024, 10:02pm UTC](https://gromacs.bioexcel.eu/t/deleting-waters-from-hydrophobic-core/9746/1 "2024-07-25T22:02:26Z")

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GROMACS version:  
GROMACS modification: Yes/No  
Here post your question

Hi! I’m trying to run a membrane simulation, but my membrane (after the solvation step) has water molecules in the hydrophobic core. What are some ways to delete these H2O molecules?

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**Author:** ![obZehn](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/obzehn/32/2629_2.png) [@obZehn](https://gromacs.bioexcel.eu/u/obZehn)\
**Post date:** [July 26, 2024, 10:22am UTC](https://gromacs.bioexcel.eu/t/deleting-waters-from-hydrophobic-core/9746/2 "2024-07-26T10:22:47Z")

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Dear @lipidsolidarity

[Here](https://manual.gromacs.org/current/how-to/special.html#adding-waters-with-genbox) there are a few suggestions from GROMACS forum. Personally, if I need it I remove them post addition by generating an index of the water molecules that are within the membrane region with `gmx select`.