Projects to turn wastewater into drinkable water are progressing in San Diego and East County, but their costs have once again spiked. In East County, a milestone is approaching as a 24-inch pipeline that will transport water from the Advanced Water Purification plant under construction in Santee to the Lake Jennings reservoir in El Cajon is on track to be completed by the end of the month. … It will convert 15 million gallons of wastewater a day into enough drinkable water to meet 30% of East County’s demands. Construction of another stretch of pipeline needed for East County’s and San Diego’s water treatment projects is beginning soon in Mission Trails Regional Park. Costs of that project recently saw a significant price increase for the city of San Diego’s $5 billion Pure Water sewage recycling system and the $1 billion Advanced Water Purification program.