In short
- Water helps if dehydration is part of the problem, and the NHS suggests keeping some by your bed at night for regular sips.
- It won't stop your mouth drying out if you sleep with it open, because saliva flow is at its lowest during sleep and mouth breathing makes that worse.
- Drinking a lot right before bed can wake you up to pee, and the American Academy of Sleep Medicine suggests cutting back on fluids before bedtime.
- Keeping your lips closed, clearing your nose and running a humidifier deal with the overnight cause more directly.
- Waking with a dry mouth plus loud snoring, gasping or daytime tiredness can be a sign of sleep apnea, so see a doctor.
Drinking water before bed helps a dry mouth only if you're short on fluids, and a few sips from a bedside glass can ease the feeling when you wake. It won't stop your mouth drying out overnight if you sleep with it open, and a big glass at bedtime can wake you up to pee. Keeping the mouth closed and the nose clear usually works better.
Does drinking water before bed help?
Drinking water before bed helps dry mouth in some cases. The NHS lists dehydration, from not drinking enough, sweating a lot or being ill, as one of the main causes of a dry mouth. If that's you, drinking more will help. The NHS suggests taking regular sips of cold water during the day and keeping some water by your bed at night. The American Dental Association also lists sipping water or sugarless, caffeine-free drinks among the ways to relieve dry mouth.
How much you drink across the day matters more than one glass at bedtime. The National Institute of Dental and Craniofacial Research (NIDCR) suggests 8 to 12 cups of water a day, or about 2 to 3 liters, for people with dry mouth.
Why does your mouth dry out at night?
Your mouth makes less saliva at night than during the day. The American Dental Association says dry mouth can get worse at night because saliva output reaches its lowest point during sleep, and that mouth breathing can make it worse.
Mouth breathing is the big one for most people. The NHS lists breathing through your mouth at night as a main cause of dry mouth, and says this can happen if you have a blocked nose or you sleep with your mouth open. Cleveland Clinic lists dry mouth, snoring and bad breath among the common symptoms of mouth breathing. A small 2016 study shows how much it changes the mouth: 10 healthy adults wore a nose clip on some nights to force mouth breathing, and their mouths became more acidic during sleep than on normal nights. The researchers noted that a drop like this has been proposed as a cause of tooth erosion and decay.
Drinking more water before bed doesn't stop you breathing through your mouth. If you're not sure whether you breathe through your mouth, signs you mouth breathe at night can help you work it out, and why do I wake up with a dry mouth? covers the other causes.
Medicines are the other common cause. The NIDCR says hundreds of medicines can reduce saliva, including some for high blood pressure, depression and bladder control. The NHS says not to stop a prescribed medicine without medical advice, even if you think it's the cause.
Can drinking water before bed backfire?
Drinking water before bed can backfire if you drink a lot. Cleveland Clinic says drinking too many fluids before bed, especially alcohol, fizzy drinks or caffeine, is one cause of nocturia, which means regularly waking more than once to pee. It suggests cutting back on fluids before bed as a first step. It also says nocturia is more likely in men and in people over 50, and that some people fall into a habit of waking up to pee even when they don't need to. The American Academy of Sleep Medicine's healthy sleep habits include reducing your fluid intake before bedtime.
The simple compromise is to drink well through the day, ease off in the evening, and keep a small glass by the bed for sips if you wake up dry.
What helps dry mouth at night?
Research: limited (what this means)The fixes that help most target the overnight cause.
Keeping your lips closed is the most direct way to stop mouth breathing during sleep. Mouth tape holds your lips together so air goes through your nose instead, and it's simple to try once you know your nose is clear. The research on tape is still early. A 2025 review in PLOS One looked at 10 small studies of mouth taping and similar methods. It found encouraging results in some, such as less snoring, but rated the evidence as poor quality and warned of serious risk when taping with a blocked nose. So check your nose first with our two-minute nose test, then read mouth tape for dry mouth for how to start.
If you'd like to try it, the tape we recommend is Titan Bamboo Silk Mouth Tape. Titan says it's a bamboo silk strip with no printed ink on the skin side, and suggests 20 to 30 minutes of daytime practice before your first night.
Check this first. Skip mouth tape and see a doctor if you snore loudly, wake up gasping, have been told you stop breathing in your sleep, or can't breathe comfortably through your nose. More on safety
A clear nose makes nose breathing possible in the first place. The NHS says a pharmacist may suggest decongestants if a blocked nose is behind your dry mouth. Our guide on how to unblock your nose before bed covers what to try.
Moist air helps too. The NIDCR suggests using a humidifier at night. The EPA advises keeping indoor humidity at or below 50% and cleaning portable humidifiers every third day. See our humidifier guide.
A few habits make dryness worse, and a few help during the day. The NIDCR suggests chewing sugarless gum or sucking sugarless hard candy to get saliva flowing, and notes that spicy or salty foods can sting a dry mouth. The NIDCR says caffeine can dry out the mouth and that tobacco and alcohol do the same, and the NHS says not to sleep with dentures in. The NHS also suggests lip balm if your lips are dry, and lip balm and mouth tape explains how to use both without the tape slipping. For a fuller list, see 10 ways to stop waking up with a dry mouth.
When is a dry mouth a sign of something else?
A dry mouth on waking can be a clue to sleep apnea. The NHLBI lists dry mouth among its symptoms, along with waking often during the night to urinate, which is easy to blame on that bedtime glass of water. In a 2020 study, 45% of people newly diagnosed with sleep apnea had a dry mouth on waking, compared with about 20% of healthy people.
The NHS lists these signs of sleep apnoea: breathing that stops and starts while you sleep, gasping, snorting or choking noises, waking up a lot, loud snoring, and feeling very tired during the day. If any apply, see a doctor before trying mouth tape, which is not a treatment for sleep apnea. Our safety page explains who should skip tape.
The NHS also says to see a GP if your mouth is still dry after a few weeks of home or pharmacy treatment, if it makes talking or eating difficult, if your mouth is painful, red, swollen or bleeding, or if you have other symptoms such as needing to pee a lot or dry eyes. It notes that a dry mouth that doesn't go away is sometimes caused by a condition such as diabetes or Sjogren's syndrome. For more, browse our sleep articles.
Read next
- Why do I wake up with a dry mouth?
- Mouth tape for dry mouth at night: what to know
- 10 ways to stop waking up with a dry mouth
Common questions
Should I drink water if I wake up with a dry mouth?
Yes, a few sips are fine. The NHS suggests keeping water by your bed at night. Try not to drink a large glass, which may mean another trip to the bathroom.
How much water should I drink for a dry mouth?
The NIDCR suggests 8 to 12 cups a day, spread through the day. Sipping steadily during the day is more useful than drinking a lot right before bed.
Why is my mouth dry at night even when I drink plenty of water?
The most common reason is breathing through your mouth while you sleep, which the NHS says can happen with a blocked nose or if you sleep with your mouth open. Medicines can also reduce saliva, and the NIDCR says hundreds of them do.
Does breathing through your mouth cause dry mouth?
Yes, it's one of the most common causes. The NHS lists breathing through your mouth at night as a main cause of dry mouth, and Cleveland Clinic names dry mouth among the usual symptoms of mouth breathing. The American Dental Association adds that saliva output is at its lowest during sleep, so breathing through an open mouth at night makes dryness worse.
Does mouth tape help with dry mouth?
If your mouth falls open at night and your nose is clear, mouth tape keeps your lips together so you breathe through your nose instead. Research on tape for dry mouth specifically is limited, so think of it as something worth trying rather than a proven fix.
Can dry mouth at night be a sign of sleep apnea?
It can. The NHLBI lists dry mouth and waking often to urinate among sleep apnea symptoms, and a 2020 study found dry mouth on waking was more than twice as common in people with sleep apnea as in healthy people.
What should I avoid before bed if I get a dry mouth?
The NIDCR says caffeine can dry out the mouth and that tobacco and alcohol dry it out too. The NHS adds not sleeping with dentures in.
Sources
- Dry mouth
- Dry mouth
- Xerostomia (dry mouth)
- Intraoral pH and temperature during sleep with and without mouth breathing
- Mouth breathing
- Nocturia
- Healthy sleep habits
- Sleep apnea: symptoms
- Xerostomia in patients with sleep apnea-hypopnea syndrome: a prospective case-control study
- Sleep apnoea
- Breaking social media fads and uncovering the safety and efficacy of mouth taping in patients with mouth breathing, sleep disordered breathing, or obstructive sleep apnea: A systematic review
- Use and care of home humidifiers
- Titan Bamboo Silk Mouth Tape
About this article
- Research
- 13 published sources, listed above.
- Evidence
- Limited. How we rate it
- Last checked
- October 10, 2026
- Funding
- Paid partner of Titan Recovery. Their ads are labeled.
- Found an error?
- Tell us. We log fixes on the corrections page.
* This content is for informational and educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure or prevent any disease or health condition. Talk to a qualified healthcare provider about your health.
