My seven-month-old is eating eight to nine tablespoons of cereal, and three to four tablespoons of bananas a day. She gets some water and I still breastfeed her three times a day. Her bowel movements seem to be difficult for her now that she's on solids.
How much liquids should she be getting? At feeding time, should she be drinking liquids with her cereal mixture? I'm concerned about her being dehydrated.
To answer your specific questions first:
A seven-month-old baby who is exclusively bottle fed will take, on average, 28 to 32 ounces per day. Since you are breastfeeding, we can't easily quantify the amount. In which case we look to output to assess hydration. Your daughter should have four to six obviously wet diapers a day. Though hard stools do go with dehydration, stools commonly get harder when solids are started. The amount and color of the urine is a more reliable sign of hydration in babies.
There is no set advice as to whether liquids and solids should be given together. Most babies want either the breast or a bottle when they first awaken and are hungriest, and then again at night as they transition into sleep. Solids are usually taken two to three times during the day when babies are hungry, while they are also awake and engaged. Most six to seven-month-old established eaters have three, four-ounce meals per day, but the amounts vary among babies.
To answer the larger question of whether a baby is getting enough to eat, we look to the weight gain. Between six and nine months, babies should gain about three pounds.
If your daughter is gaining well and urinating often, the likelihood is that she is getting enough liquids and calories.