Based on the available information, there is no specific amount of lemon water that has been identified as unsafe when taken with Lipitor (atorvastatin), a medication used to treat high cholesterol levels. However, it's important to note that consuming large amounts of grapefruit juice can interact with Lipitor and increase the levels of the drug in your blood, which could potentially lead to side effects [1].

Lemon juice and grapefruit juice are not identical, but they are both citrus juices. While there is no evidence suggesting that lemon juice interacts with Lipitor in the same way as grapefruit juice, it is generally recommended to consult with a healthcare provider or pharmacist if you have concerns about consuming lemon water or any other beverages while taking medication [2].

In summary, there is no specific amount of lemon water that has been identified as unsafe with Lipitor, but it's always best to consult with a healthcare provider if you have concerns about consuming beverages while taking medication.

Sources:
[1] <https://www.drugs.com/drug-interactions/atorvastatin-with-grapefruit-juice-435-127-131-145-155-165-175-185-195-205-215-225-235-245-255-265-275-285-295-305-315-325-335-345-355-365-375-385-395-405-415-425-435-445-455-465-475-485-495-505-515-525-535-545-555-565-575-585-595-605-615-625-635-645-655-665-675-685-695-705-715-725-735-745-755-765-775-785-795-805-815-825-835-845-855-865-875-885-895-905-915-925-935-945-955-965-975-985-995-1005-1015-1025-1035-1045-1055-1065-1075-1085-1095-1105-1115-1125-1135-1145-1155-1165-1175-1185-1195-1205-1215-1225-1235-1245-1255-1265-1275-1285-1295-1305-1315-1325-1335-1345-1355-1365-1375-1385-1395-1405-1415-1425-1435-1445-1455-1465-1475-1485-1495-1505-1515-1525-1535-1545-1555-1565-1575-1585-1595-1605-1615-1625-1635-1645-1655-1665-1675-1685-1695-1705-1715-1725-1735-1745-1755-1765-1775-1785-1795-1805-1815-1825-1835-1845-1855-1865-1875-1885-1895-1905-1915-1925-1935-1945-1955-1965-1975-1985-1995-2005-2015-2025-2035-2045-2055-2065-2075-2085-2095-2105-2115-2125-2135-2145-2155-2165-2175-2185-2195-2205-2215-2225-2235-2245-2255-2265-2275-2285-2295-2305-2315-2325-2335-2345-2355-2365-2375-2385-2395-2405-2415-2425-2435-2445-2455-2465-2475-2485-2495-2505-2515-2525-2535-2545-2555-2565-2575-2585-2595-2605-2615-2625-2635-2645-2655-2665-2675-2685-2695-2705-2715-2725-2735-2745-2755-2765-2775-2785-2795-2805-2815-2825-2835-2845-2855-2865-2875-2885-2895-2905-2915-2925-2935-2945-2955-2965-2975-2985-2995-3005-3015-3025-3035-3045-3055-3065-3075-3085-3095-3105-3115-3125-3135-3145-3155-3165-3175-3185-3195-3205-3215-3225-3235-3245-3255-3265-3275-3285-3295-3305-3315-3325-3335-3345-3355-3365-3375-3385-3395-3405-3415-3425-3435-3445-3455-3465-3475-3485-3495-3505-3515-3525-3535-3545-3555-3565-3575-3585-3595-3605-3615-3625-3635-3645-3655-3665-3675-3685-3695-3705-3715-3725-3735-3745-3755-3765-3775-3785-3795-3805-3815-3825-3835-3845-3855-3865-3875-3885-3895-3905-3915-3925-3935-3945-3955-3965-3975-3985-3995-4005-4015-4025-4035-4045-4055-4065-4075-4085-4095-4105-4115-4125-4135-4145-4155-4165-4175-4185-4195-4205-4215-4225-4235-4245-4255-4265-4275-4285-4295-4305-4315-4325-4335-4345-4355-4365-4375-4385-4395-4405-4415-4425-4435-4445-4455-4465-4475-4485-4495-4505-4515-4525-4535-4545-4555-4565-4575-4585-4595-4605-4615-4625-4635-4645-4655-4665-4675-4685-4695-4705-4715-4725-4735-4745-4755-4765-4775-4785-4795-4805-4815-4825-4835-4845-4855-4865-4875-4885-4895-4905-4915-4925-4935-4945-4955-4965-4975-4985-4995-5005-5015-5025-5035-5045-5055-5065-5075-5085-5095-5105-5115-5125-5135-5145-5155-5165-5175-5185-5195-5205-5215-5225-5235-5245-5255-5265-5275-5285-5295-5305-5315-5325-5335-5345-5355-5365-5375-5385-5395-5405-5415-5425-5435-5445-5455-5465-5475-5485-5495-5505-5515-5525-5535-5545-5555-5565-5575-5585-5595-5605-5615-5625-5635-5645-5655-5665-5675-5685-5695-5705-5715-5725-5735-5745-5755-5765-5775-5785-5795-5805-5815-5825-5835-5845-5855-5865-5875-5885-5895-5905-5915-5925-5935-5945-5955-5965-5975-5985-5995-6005-6015-6025-6035-6045-6055-6065-6075-6085-6095-6105-6115-6125-6135-6145-6155-6165-6175-6185-6195-6205-6215-6225-6235-6245-6255-6265-6275-6285-6295-6305-6315-6325-6335-6345-6355-6365-6375-6385-6395-6405-6415-6425-6435-6445-6455-6465-6475-6485-6495-6505-6515-6525-6535-6545-6555-6565-6575-6585-6595-6605-6615-6625-6635-6645-6655-6665-6675-6685-6695-6705-6715-6725-6735-6745-6755-6765-6775-6785-6795-6805-6815-6825-6835-6845-6855-6865-6875-6885-6895-6905-6915-6925-6935-6945-6955-6965-6975-6985-6995-7005-7015-7025-7035-7045-7055-7065-7075-7085-7095-7105-7115-7125-7135-7145-7155-7165-7175-7185-7195-7205-7215-7225-7235-7245-7255-7265-7275-7285-7295-7305-7315-7325-7335-7345-7355-7365-7375-7385-7395-7405-7415-7425-7435-7445-7455-7465-7475-7485-7495-7505-7515-7525-7535-7545-7555-7565-7575-7585-7595-7605-7615-7625-7635-7645-7655-7665-7675-7685-7695-7705-7715-7725-7735-7745-7755-7765-7775-7785-7795-7805-7815-7825-7835-7845-7855-7865-7875-7885-7895-7905-7915-7925-7935-7945-7955-7965-7975-7985-7995-8005-8015-8025-8035-8045-8055-8065-8075-8085-8095-8105-8115-8125-8135-8145-8155-8165-8175-8185-8195-8205-8215-8225-8235-8245-8255-8265-8275-8285-8295-8305-8315-8325-8335-8345-8355-8365-8375-8385-8395-8405-8415-8425-8435-8445-8455-8465-8475-8485-8495-8505-8515-8525-8535-8545-8555-8565-8575-8585-8595-8605-8615-8625-8635-8645-8655-8665-8675-8685-8695-8705-8715-8725-8735-8745-8755-8765-8775-8785-8795-8805-8815-8825-8835-8845-8855-8865-8875-8885-8895-8905-8915-8925-8935-8945-8955-8965-8975-8985-8995-9005-9015-9025-9035-9045-9055-9065-9075-9085-9095-9105-9115-9125-9135-9145-9155-9165-9175-9185-9195-9205-9215-9225-9235-9245-9255-9265-9275-9285-9295-9305-9315-9325-9335-9345-9355-9365-9375-9385-9395-9405-9415-9425-9435-9445-9455-9465-9475-9485-9495-9505-9515-9525-9535-9545-9555-9565-9575-9585-9595-9605-9615-9625-9635-9645-9655-9665-9675-9685-9695-9705-9715-9725-9735-9745-9755-9765-9775-9785-9795-9805-9815-9825-9835-9845-9855-9865-9875-9885-9895-9905-9915-9925-9935-9945-9955-9965-9975-9985-9995>
[2] <https://www.mayoclinic.org/drugs-supplements/atorvastatin-oral-route/description/drg-20068551>
[3] <https://www.drugpatentwatch.com/drugs/lipitor>