How long does it take after drinking around 4-5 lts of water for water poison kick in? i had about 4 or 5 liters within 2 hours. should i see the er?

Depends: You asked the question 15 hours ago and should have discharged most of the water in urine by now. Why did you drink 4-5 liters in 2 hours? If you were trying to harm yourself, you need to see a psychiatrist. Wish you good health! For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex, if you have sex. Get HPV vaccine, if you are under 27 years of age.