Dehydration causes vertigo.
HEALTH Perhaps as a child you played Pin the Tail on the Donkey. You were willingly blindfolded and spun around until disoriented before attempting to walk towards a board and attach a paper donkey tail. The unavoidable misplacement amused onlookers.  In the game, the participant usually regains equilibrium shortly after the veil is removed. If you can imagine remaining in the state of disorientation without the blindfold then you have entered the tortuous mind of vertigo sufferers.
Vertigo Dries Up Social Interaction
Disequilibrium can bemuse vertigo sufferers for hours, days or longer, often accompanied by nausea, photophobia and hyperacusis (sonophobia). It interferes with a person's fitness routine, work, and social interaction. Some describe it as a never-ending roller-coaster decent. Others say that it feels like a hangover without the alcohol.  Either way, it's not fun and games.
A sudden change in position may trigger vertigo. The "good" kind lasts less than a minute. For others, there's an aura, or tell-tale sign, portending an unproductive day. Medical literature distinguishes between migraines, dizziness and vertigo. "Dizzy" may be defined as a feeling of faintness or lightheadedness. However, symptoms can overlap. A patient may experience migrainous vertigo (vertiginous migraine), for example.  Those debilitated by vertigo often deplete financial resources in hopes of emerging from their social drought of hibernation.
Weeding Out The Source of Vertigo
To improve a garden, homeowners might survey neighbors, hire a professional landscaper or even obtain geological soil samples with good, albeit expensive, results. Likewise, many professional tests can be performed to diagnose vertigo.
If trauma has been involved or unexplained dizziness occurs, particularly in association with other symptoms like diarrhea, impaired vision, depreciated hearing or memory loss, a doctor's diagnosis is prudent. Generally, physicians perform an MRI to rule out tumors. This may be ordered in conjunction with a referral to an otolaryngologist (Ear, Nose & Throat doctor) for further evaluation and testing.
During a patient consultation, questions often focus on when symptoms first began, what current medications are being taken, whether vision is blurred, if there is any pain associated with the disequilibrium, does (s)he feel faint, how much alcohol is consumed daily, whether the patient feels (s)he is moving or encircled by the environment.  The questions, alone, could make one's head spin. An often overlooked question is: "How much water do you drink daily?"
Though it may not be the motivation of most healthcare providers, counseling, pain medication, psychiatric visits, vestibular and auditory tests can be monetized. With the potential for a life-threatenting ailment, insurance companies pay up. And the compensation keeps doctors in business. Chronic sufferers may wonder if this contributes to treatments that divert attention away from such a simple, natural solution. Is a such an inexpensive remedy as water even plausible?
Getting To The Root of The Problem
To maintain lush green lawns, grass can be mowed, treated with chemical fertilizers; weeds can be removed but in most cases, browning grass signals the need for water. Putting chemical fertilizer on a lawn with insufficient water will do more damage than good. Similarly, treating vertigo symptoms with prescriptions does not remedy the root problem when the cause is dehydration. It is theorized that unnecessary drugs may contribute towards toxicity (another cause of vertigo) since the body's water conservation effort results in retention of a higher concentration of chemicals.
According to Joshua Gowin, PhD, brain cells require a delicate balance between water and various elements to operate, and when too much water is lost, that balance is disrupted. Brain cells lose efficiency.  A very common cause of vertigo that worsens with a change in position is dehydration. Dehydration often follows vomiting or diarrhea. Vertigo frequently causes nausea and vomiting, so it may be hard to distinguish inner ear problems from dehydration.  Nevertheless, such a distinction is key to ascertaining proper care. An article in the Journal of the American Medical Association by A.D. Weinberg, MD, et al. concludes: "In patients identified as being at risk for possible dehydration, an interdisciplinary care plan with regard to prevention of clinically significant dehydration is critical if maximum benefit is to result." 
Many negative symptoms associated with a hangover are caused by dehydration – headaches, fatigue, and dry mouth.  How can vertigo be caused by dehydration when a patient doesn't feel thirsty? If someone has been dehydrated for an extended time, the thirst mechanism shuts down. The feeling of thirst is absent until the mouth is literally dry or the body is about two glasses low. It’s a strange phenomenon, but if one begins regularly drinking water, the thirst mechanism returns. 
Immerse Yourself In Water
Obviously, water doesn't cure every case of vertigo. As discussed earlier, there can be physiological causes or even environmental toxins.  But it is good to monitor water intake since the average person expells 90 ounces of water daily through urine and perspiration. Aim to drink half your body weight (pounds) in ounces. At 150 pounds, the human body requires about 75 ounces of water throughout the day to remain hydrated. Fluid requirements increase at higher altitudes and during physical exertion.  Generally, the limit for the largest person is 16 glasses per day. People with nephrotic syndrome can have extreme thirst due to kidney dysfunction. A nephrologist should individually advise such ones on diet and fluid intake.
If you aren't in the habit of drinking much water, you may need to remind yourself by associating water consumption with regular activities. Have a glass first thing in the morning. Have another before and after each meal. Keep a bottle on your desk at work and take one with you during workouts. Offset each caffeinated beverage with an equal amount of pure water. 
It takes time to thoroughly rehydrate cells throughout your body so don’t expect immediate results. But if you have other symptoms of dehydration like dry skin and hair, dark or infrequent urine, then you should evaluate your water intake even in the absence of vertigo. Though you may have tried everything but the kitchen sink, a simple cure for this ailment may be purified water.  Check references below or use the search box on this site to locate more articles on vertigo.
- Pin the Tail on the Donkey. en.wikipedia.org
- The Dizzy Patient. family-fauquierent.net
- The point prevalence of dizziness or vertigo in migraine--and factors that influence presentation. pubmed.gov
- Dizziness: Preparing for your appointment. mayoclinic.com
- Why Your Brain Needs Water. psychologytoday.com
- Causes of Vertigo. firstaid.about.com
- Dehydration: Evaluation and Management in Older Adults. JAMA
- Hangover Remedies and Prevention? chemistry.about.com
- Can Dizziness And Vertigo Be Caused By Dehydration? greatposture.com
- Dizzying Solution to Vertigo. Health.ClinicalPosters.com
- Dehydration: Avoiding the Dry Spell. Health.ClinicalPosters.com
- Prescription Tap Water: What Drugs Are We Taking With Our Drugs? huffingtonpost.com